USPS v. PRC ( 2015 )


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  •  United States Court of Appeals
    FOR THE DISTRICT OF COLUMBIA CIRCUIT
    Argued November 20, 2014             Decided May 12, 2015
    No. 13-1308
    UNITED STATES POSTAL SERVICE,
    PETITIONER
    v.
    POSTAL REGULATORY COMMISSION,
    RESPONDENT
    ALLIANCE OF NONPROFIT MAILERS, ET AL.,
    INTERVENORS
    On Petition for Review of an Order
    of the Postal Regulatory Commission
    David C. Belt, Attorney, U.S. Postal Service, argued the
    cause for petitioner. With him on the briefs was Morgan E.
    Rehrig, Attorney. Stephan J. Boardman, Attorney, entered an
    appearance.
    Dana L. Kaersvang, Attorney, U.S. Department of
    Justice, argued the cause for respondent. On the brief were
    Stuart F. Delery, Assistant Attorney General, Michael S.
    Raab and Benjamin M. Shultz, Attorneys, David A. Trissell,
    General Counsel, Postal Regulatory Commission, and R.
    Brian Corcoran, Deputy General Counsel.
    2
    William B. Baker, David M. Levy, William J. Olson,
    Jeremiah L. Morgan, and John S. Miles were on the brief for
    intervenors Alliance of Nonprofit Mailers, et al. in support of
    respondent.
    Matthew D. Field entered an appearance.
    Before: TATEL, Circuit Judge, WILKINS, Circuit Judge,
    and EDWARDS, Senior Circuit Judge.
    Opinion for the Court filed by Senior Circuit Judge
    EDWARDS.
    EDWARDS, Senior Circuit Judge: On November 21, 2013,
    the Postal Regulatory Commission (“Commission”) issued
    Order No. 1890, Order on Price Adjustments for Market
    Dominant Products and Related Mail Classification Changes
    (“Order on Price Adjustments”), reprinted at J.A. 361. The
    Order rejected proposals that had been submitted by the
    United States Postal Service (“Postal Service” or “Service”)
    to implement price adjustments to certain of its market-
    dominant products as well as classification changes in
    conjunction with the price changes. The United States Postal
    Service now seeks review of this Order.
    The Postal Accountability and Enhancement Act (“Act”)
    generally forbids the Postal Service from raising the rates on
    its market-dominant products faster than the rate of inflation.
    
    39 U.S.C. § 3622
    (d)(1)(A). Under the Act, the Commission is
    charged with “regulating rates and classes for market-
    dominant products,” 
    id.
     § 3622(a), which includes
    promulgating regulations implementing the inflation-based
    price cap. Pursuant to this authority, the Commission has
    adopted regulations requiring the Postal Service to account for
    the effects that reclassifying mail would have on the rates
    3
    charged for that mail. See 
    39 C.F.R. § 3010.23
    (d). For
    example, in accordance with these regulations, if the Postal
    Service deletes a price from its price list, thus forcing a
    reclassification of the mail that had been charged that price
    during the prior year, it must account for the reclassification
    when computing any accompanying changes in rates. Thus, if
    the reclassified mail would now be charged a higher price –
    for instance, because the deleted price was a temporary
    discount – then the extra cost for shipping that mail counts
    against the price cap. The deletion of the discounted rate
    causes a reclassification of certain mail and effectively raises
    the rate on the previously discounted mail.
    In April 2013, the Postal Service amended its mail
    preparation requirements so that mail pieces prepared
    according to the “basic-service Intelligent Mail” standard
    would no longer be eligible for a discounted “automation”
    rate available to mailers who use technologies to increase the
    Postal Service’s efficiency. Implementation of Full-Service
    Intelligent Mail Requirements for Automation Prices, 
    78 Fed. Reg. 23,137
    , 23,137 (Apr. 18, 2013). In subsequent rate
    change proceedings before the Commission, mailers objected
    that this change in mail preparation requirements constituted a
    classification change resulting in an increase in rates that must
    be counted against the Postal Service’s price cap. The Postal
    Service disagreed, arguing that mail preparation changes that
    did not actually alter the posted prices were not “changes in
    rates” within the plain meaning of the price cap statute or
    “classification changes” within the plain meaning of the
    Commission’s regulations, and therefore their effects did not
    count toward the price cap.
    The mailers prevailed before the Commission. See Order
    on Price Adjustments at 1–2. The Commission held “that the
    new mail preparation requirements redefine rate cells because
    4
    they require mailers to alter a basic characteristic of a mailing
    in order for the mailing to qualify for the same rate category
    for which it was eligible before the change in requirements.”
    
    Id. at 18
    . The Commission thus concluded that the rate effects
    of the mail preparation requirements change, combined with
    the Postal Service’s other proposed rate increases, would
    violate the inflation-based price cap. 
    Id. at 2
    .
    The principal issue in this case is whether the
    Commission is correct in its view that its rate cap authority
    extends beyond the regulation of posted rates to regulation of
    Postal Service operational rules that have “rate effects.” The
    Postal Service contends that the Act and applicable
    regulations plainly forbid the Commission from
    characterizing mail preparation requirements as “changes in
    rates.” In addition, the Postal Service argues that the
    Commission’s Order on Price Adjustments is arbitrary and
    capricious because the standard that it invokes to determine
    when changes in mail preparation requirements constitute
    “changes in rates” is incomprehensible.
    In our view, the Act and applicable regulations are
    ambiguous with respect to whether the Commission’s
    authority extends to the regulation of operational rules that
    have “rate effects.” We therefore reject the Postal Service’s
    claim that the “plain meaning” of the Act and regulations
    positively forbid the Commission from counting an
    operational change that has rate effects as a “change in rates.”
    The Commission’s interpretation of the Act thus does not fail
    under Step One of Chevron U.S.A. Inc. v. Natural Resources
    Defense Council, Inc., 
    467 U.S. 837
     (1984). We agree with
    the Postal Service, however, that the Commission’s Order
    cannot survive arbitrary and capricious review. The standard
    enunciated by the Commission to determine when
    requirements changes are “changes in rates” seems boundless
    5
    and, thus, unreasonable; and the Commission’s inconsistent
    application of the standard in this case proves the point.
    An agency action must be supported by “reasoned
    decisionmaking,” whether taken in the course of rulemaking
    or adjudication. Allentown Mack Sales & Serv., Inc. v. NLRB,
    
    522 U.S. 359
    , 374 (1998). The Commission’s judgment in
    this case “lacks any coherence. We therefore owe no
    deference to [the Commission’s] purported expertise because
    we cannot discern it.” Tripoli Rocketry Ass’n, Inc. v. Bureau
    of Alcohol, Tobacco, Firearms, & Explosives, 
    437 F.3d 75
    , 77
    (D.C. Cir. 2006). We therefore remand the case to the
    Commission to enunciate an intelligible standard and then
    reconsider its decision in light of that standard.
    I.   BACKGROUND
    A. The Cap on Changes in the Postal Service’s Rates
    “In 1970, what was formerly the cabinet-level Post Office
    Department was transformed by statute into the modern
    government-owned corporation known as the United States
    Postal Service.” USPS v. Postal Regulatory Comm’n, 
    599 F.3d 705
    , 706 (D.C. Cir. 2010). As part of that
    transformation, Congress created the Postal Rate Commission
    to oversee a system in which the Postal Service established
    rates based on its actual costs, with the goal of breaking even.
    See United Parcel Serv., Inc. v. USPS, 
    184 F.3d 827
    , 829–30
    (D.C. Cir. 1999). After criticism that the cost-based
    ratemaking model failed to incent the Postal Service to
    operate efficiently, and for other reasons, Congress reformed
    the ratemaking scheme by enacting the Postal Accountability
    and Enhancement Act in 2006.
    6
    The Act separated the Postal Service’s product classes
    into two differently regulated groups: “market-dominant
    products” and “competitive products.” See USPS v. Postal
    Regulatory Comm’n, 
    676 F.3d 1105
    , 1107 (D.C. Cir. 2012).
    “Market-dominant products” include the various products for
    which the Postal Service enjoys a statutory monopoly, or for
    which the Postal Service exercises sufficient market power so
    that it can effectively dictate the price of such products
    without risk of losing much business to competing firms. See
    
    39 U.S.C. § 3642
    (b)(1), (2). Remaining products, for which
    the Postal Service faces meaningful market competition, are
    classified as “competitive products” and are not at issue in
    this case.
    The Act completely reformed the ratemaking system for
    market-dominant products. To alleviate concerns that the
    Postal Service would improperly leverage its monopoly
    powers over these products, the Act subjected them to a price
    cap, forbidding “changes in rates” to rise faster than inflation:
    The system for regulating rates and classes for market-
    dominant products shall—
    (A) include an annual limitation on the percentage
    changes in rates to be set by the Postal Regulatory
    Commission that will be equal to the change in the
    Consumer Price Index for All Urban Consumers . . . over
    the most recent available 12-month period preceding the
    date the Postal Service files notice of its intention to
    increase rates[.]
    
    Id.
     § 3622(d)(1)(A).
    The price cap does not apply directly to every individual
    product, however. Rather, it applies to each “class” of
    products, as defined by statute. Id. § 3622(d)(2)(A). As a
    7
    result, the Postal Service can raise the price of one product in
    a mail “class” by more than the rate of inflation if that over-
    inflation increase is offset by lower rises or reductions in
    other products in the class. For example, the Postal Service
    can raise the rate of one kind of first-class mail by more than
    the rate of inflation as long as it offsets that increase with a
    lower rise in another kind of first-class mail.
    In addition, because market-dominant prices can be
    raised to track inflation regardless of the Postal Service’s
    actual costs, the Postal Service can keep savings it creates
    through cost cutting. On the other hand, if the Postal Service’s
    costs rise faster than the rate of inflation then, barring
    extraordinary circumstances justifying a rate increase, the
    Postal Service may not be able to cover its costs. Thus, the
    inflation-based price cap protects mailers from the
    “unreasonable use of the Postal Service’s statutorily-granted
    [and de facto] monopoly” power while creating new pricing
    flexibility, incentives for the Postal Service to reduce costs,
    and the opportunity for the Postal Service to earn a profit. S.
    REP. NO. 108-318, at 19 (2004).
    B. The Commission’s Implementation of the Price Cap
    The Act also reformed the Postal Rate Commission into
    the Postal Regulatory Commission and required it to
    promulgate regulations “whereby the Postal Service may
    adjust rates not in excess of the” price cap. 
    39 U.S.C. § 3622
    (d)(1)(D). The Commission’s regulations seek to
    ensure that the class-level price cap serves as an effective
    limit on the Postal Service’s rates by plugging several
    potential gaps in the cap. Thus, for example, the
    Commission’s rules ensure that the Postal Service may not
    generate extra revenue beyond the price cap by taking
    advantage of the different volume levels of different products
    8
    within a class to raise rates unevenly while technically
    complying with the class-level price cap. To achieve this, the
    Commission has promulgated regulations specifying that the
    calculation of a “change in rates” in a class should be
    weighted by the mail volume of any given rate cell in a class.
    
    39 C.F.R. § 3010.23
    (b). So, if the Postal Service has two rate
    cells in a given class but one of them accounts for the lion’s
    share of the mail volume, any increase in the rate for that rate
    cell will be weighted according to volume when determining
    its contribution toward the class-wide rate change cap. Small
    increases in the rate for small-volume rate cells cannot be
    used to obscure large increases in the rate for the large-
    volume rate cells that generate the most revenue. By default,
    the volume levels of the various products are to “be obtained
    from the most recent available 12 months” of data. 
    Id.
    § 3010.23(d)(1).
    The Commission’s regulations also seek to prevent the
    Postal Service from evading the price cap by shifting mail to
    more expensive rates. Because the Postal Service often
    changes the classification of its mail, for example by adding,
    deleting, or redefining rate cells, it is possible that some mail
    will shift between different rates. The Commission
    determined that shifting identical mailpieces between
    different rates would constitute “changes in rates” for those
    mailpieces. The Commission thus required the Postal Service
    to factor the effects of classification changes into the
    calculation of changes in rates by adjusting the volume
    associated with each rate cell in sync with any changes to the
    treatment of mailpieces. The applicable regulation states:
    The Postal Service shall make reasonable adjustments to
    the billing determinants [i.e., volume levels] to account
    for the effects of classification changes such as the
    introduction, deletion, or redefinition of rate cells.
    9
    Id. § 3010.23(d)(2).
    As noted above, this regulation prevents the Postal
    Service from circumventing the price cap by shifting mail
    volume into more expensive rate cells. If a discounted rate is
    “deleted,” forcing a mailer to pay a higher price for their piece
    of mail, that price increase would be captured and counted
    toward the price cap. The regulation thus codifies an
    important precept: that the rate on the discounted mail has
    essentially been raised by being forced into a higher rate cell,
    independently of whether the posted price in either the new or
    original rate cell has been changed.
    Moreover, at the urging of the Postal Service and to
    simplify the calculation of the effect of classification changes,
    the Commission has required the Postal Service to use
    historical volume data and known mail characteristics (rather
    than forecasts of changes in mailer behavior) when
    determining the effects of classification changes. The
    applicable regulation essentially requires the Postal Service to
    assume a “constant mail mix” – measuring changes in rates as
    if last year’s mail were being sent under the new proposed
    rates and rules. The regulation states:
    Whenever possible, adjustments shall be based on known
    mail characteristics or historical volume data, as opposed
    to forecasts of mailer behavior.
    Id. § 3010.23(d)(3). Although the precise language of the
    regulation has changed several times, its essence has
    remained the same: if last year’s market-dominant mail in a
    given class, sent according to the new rates and classification
    rules, allow the Postal Service to earn more revenues than the
    inflation-adjusted maximum, the rates violate the cap.
    10
    C. The Mail Preparation Requirements Change
    As indicated at the outset of this opinion, this case raises
    questions regarding the scope of the Commission’s authority
    to regulate “changes in rates” pursuant to the price cap statute
    and its own regulations. The issue between the Postal Service
    and mailers arose when the Service changed mail preparation
    requirements that would have the likely effect of changing
    rates paid by certain mailers for sending the same mailpieces
    that they sent in the prior year. The parties dispute, among
    other things, whether such a change is a “classification”
    change within the meaning of the Commission’s regulations,
    and whether such a classification change can result in a
    “change in rates” within the meaning of the Act.
    Understanding the mail preparation requirements change and
    its potential rate effects serves as a crucial starting point in
    this case.
    The Postal Service offers “automation discounts” on
    many of its market-dominant products to mailers who are
    willing to prepare and tender mailpieces using technologies
    that reduce the Postal Service’s costs. While the official,
    posted rates for these discounts are subject to approval by the
    Commission, the Postal Service retains discretion to define
    eligibility for many of these automation rates through its
    power to create mail preparation requirements. For example,
    the Postal Service may sometimes define which automation
    procedures entitle mailers to the discounts. These procedures
    are published in the Domestic Mail Manual (“Manual”),
    which contains the detailed operational rules governing the
    mail products described in the formal Mail Classification
    Schedule overseen by the Commission. See Br. of the U.S.
    Postal Serv. 13.
    11
    One form of automation approved by the Manual is the
    use of “Intelligent Mail” standards, which essentially involve
    affixing barcodes to mailpieces to enable the Postal Service to
    simplify mail acceptance, processing, and tracking. Since
    January 2009, the Postal Service has allowed mailers to use
    two different Intelligent Mail standards, receiving two
    different discounted rates: “basic-service” Intelligent Mail, a
    less demanding standard that receives a smaller discount; and
    “full-service” Intelligent Mail, a more demanding standard
    that receives a larger discount. Basic-service Intelligent Mail
    requires mailers to affix a barcode to each mailpiece
    containing some basic information about the shipment, and to
    schedule pick-up through a designated electronic scheduling
    system. See generally Implementation of Intelligent Mail®
    Barcodes, 
    73 Fed. Reg. 1158
    , 1160 (Jan. 7, 2008). Full-
    service Intelligent Mail requires mailers to affix to each
    mailpiece a barcode that uniquely identifies that mailpiece; to
    place specialized barcodes on trays, sacks, and other
    containers; to submit postage and mail shipment information
    electronically; and to schedule certain pickups using a
    specified electronic system. See generally 
    id.
     at 1159–60.
    In April 2013, the Postal Service provided public notice
    that it was amending the Manual to change the eligibility
    requirements for its automation rates, promulgating the
    regulation that is at the heart of the dispute in this case. 
    78 Fed. Reg. 23,137
    . The Postal Service announced that use of
    the basic-service Intelligent Mail standard would no longer
    entitle mailers for any automation discount. Meanwhile, the
    full-service Intelligent Mail discount would remain
    unchanged. For that reason, mailers using the basic-service
    standard who wanted to retain an automation discount would
    have to upgrade their systems to full-service Intelligent Mail,
    but would be rewarded with the greater full-service discount.
    Mailers who did not upgrade their systems to comply with the
    12
    full-service requirements would have to pay the higher,
    undiscounted rates. The Manual change did not actually
    change the posted automation rates; it changed only the
    eligibility rules according to which mailpieces could qualify
    for those rates.
    D. The Proceedings Before the Commission
    In September 2013, the Postal Service separately notified
    the Commission that it intended to raise its posted prices for a
    variety of market-dominant products. Order on Price
    Adjustments at 1. The parties did not dispute that these
    noticed price increases, by themselves, fell within the
    inflation-based price cap established by statute. Various
    commenters objected to the rate increases, however, stating
    that they did not take account of the changes to mail
    preparation requirements eliminating basic-service Intelligent
    Mail’s eligibility for an automation discount. That change,
    they argued, was a “classification change” within the meaning
    of 
    39 C.F.R. § 3010.23
    (d) because it made basic-service mail
    of the kind sent in the prior year ineligible for an automation
    rate; in other words, it “redefined” the discounted rate cell and
    reclassified the basic-service mail into a higher rate cell. The
    commenters further argued that this change resulted in a
    “change in rates” for basic-service Intelligent Mail within the
    meaning of the price cap statute because those same basic-
    service mailpieces would now be charged a higher rate. Thus,
    the commenters argued that if the Postal Service’s rate change
    proposal was adjusted to account for the supposed change in
    rates arising from the mail preparation requirements, the
    Postal Service had exceeded the price cap.
    The Postal Service disagreed. In the proceedings before
    the Commission, the Postal Service argued that the price cap
    statute and regulation forbid the Commission from
    13
    considering the effects of Manual changes as changes in rates.
    Regarding the price cap language of 
    39 U.S.C. § 3622
    (d)(1)(A), the Postal Service argued that Manual
    changes were not “changes in rates” because they did not
    actually change the rates posted in the formal Mail
    Classification Schedule. According to the Postal Service,
    changes to the mail preparation requirements in the Manual
    merely changed the requirements to obtain an existing rate.
    The Postal Service insisted that the plain language of the
    statute could not apply to changes that left the posted rate the
    same.
    Regarding the Commission’s regulation, the Postal
    Service claimed that Section 3010.23(d), requiring the Postal
    Service to make adjustments for “classification changes such
    as the introduction, deletion, or redefinition of rate cells,”
    does not apply to operational changes made in the Manual.
    Instead, the Postal Service contended that the only
    “classification changes” subject to the rule were changes to
    the Mail Classification Schedule overseen and approved by
    the Commission. Order on Price Adjustments at 12. The
    Postal Service additionally argued that it expected that most
    mailers would comply with the changes to the mail
    preparation requirements, and that the Commission should
    therefore not assume when calculating the change in rates that
    all basic-service mailers would begin paying higher rates. 
    Id. at 13
    .
    Lastly, the Postal Service argued that construing the price
    cap to apply to mail preparation changes would seriously blur
    the line between the Postal Service’s authority to govern day-
    to-day operational issues and the Commission’s authority to
    manage rates and classes for market-dominant products, and
    that doing so would be inconsistent with the Commission’s
    treatment of mail preparation requirement changes in the past.
    14
    See 
    id.
     at 12–13. The Postal Service expressed alarm that
    interpreting “changes in rates” to apply to all mail preparation
    requirement changes would greatly reduce the flexibility that
    the Postal Service needs to run its business operations.
    The Commission largely agreed with the objectors. The
    Commission held that “[w]hether one characterizes the
    [Manual] change as a redefinition or a deletion [of a rate cell],
    or both, it is a classification change with rate effects that must
    be recognized in calculating whether the proposed changes in
    rates comply with the annual limitation established in 
    39 U.S.C. § 3622
    (d)(1)(A).” Order on Price Adjustments at 15.
    Noting that “the focus of the comments has been on the
    redefinition of rate cells,” 
    id.,
     the Commission set out its legal
    standard for when a change in mail preparation requirements
    constitutes a redefinition of a rate cell. The test, it held, was
    whether
    the new mail preparation requirements . . . require
    mailers to alter a basic characteristic of a mailing in
    order for the mailing to qualify for the same rate category
    for which it was eligible before the change in
    requirements.
    
    Id. at 18
     (emphasis added).
    The Commission rejected the Postal Service’s arguments
    that the “classification changes” mentioned by the regulations
    were limited to the Mail Classification Schedule
    superintended by the Commission, noting its own authority to
    interpret the regulations and that the Postal Service and other
    commenters had specifically discussed “when changes in mail
    preparation requirements have significant rate implications”
    during the regulations’ design. 
    Id.
     at 19–20. Additionally, the
    15
    Commission dismissed the Postal Service’s fear that
    “deeming some new mail preparation requirements to result in
    rate adjustments will lead to deeming all new mail
    preparation requirements to result in rate adjustments,” stating
    that “[t]he Commission has not and will not indiscriminately
    treat all new mail preparation requirements as rate
    adjustments.” 
    Id. at 25
    . Pointing to its “basic characteristic of
    a mailing” standard, the Commission argued it would be able
    to distinguish between new mail preparation requirements that
    changed rates and those that did not.
    Applying its new standard to the Manual change
    involving the Intelligent Mail standards, the Commission
    concluded that the new rules require mailers to “make
    changes to the basic characteristics of their mailings in order
    to continue to qualify for the automation discounts for which
    they are currently eligible.” 
    Id. at 29
    . In reaching this
    conclusion, the Commission noted that mailers must apply
    unique barcodes to each mailpiece; apply barcodes to trays,
    tubs, sacks, and containers; ensure that the barcodes at each
    level are interconnected; and use a designated electronic
    system to schedule appointments and provide electronic
    documentation. According to the Commission, these
    “change[s to] their mailing practices” constitute “change[s to]
    the basic characteristics of a mailing.” 
    Id. at 30
    . The
    Commission also concluded, in the alternative, that the
    Manual change was the “deletion” of a rate cell because, after
    the change, no mailers would be eligible for the lower
    discounted rate previously applied to basic-service Intelligent
    Mail users. 
    Id.
     at 31–33.
    The Commission also dismissed the Postal Service’s
    objections to its requirement that the Postal Service use
    historical data, assuming that no basic-service mailers would
    upgrade to full-service mail, when calculating the rate effects
    16
    of the Manual change. 
    Id.
     at 33–35. While the Postal Service
    argued that, in its experience, most mailers would make the
    needed upgrades and therefore qualify for the lower rate, the
    Commission pointed out that its rate change calculation rules
    require the Postal Service to use known mail characteristics or
    historical volume data whenever possible, as opposed to
    forecasts of mailer behavior. 
    Id. at 33
    ; see also 
    39 C.F.R. § 2010.23
    (d)(3). It noted that the historical volume approach
    had been proposed by and, until recently, supported by the
    Postal Service as a necessary and wise expedient given the
    difficulties and controversies surrounding use of forecasts of
    mailer behavior in ratemaking proceedings. Order on Price
    Adjustments at 33–35.
    The Commission concluded that, since the mail
    preparation requirement changes resulted in increases in rates
    on basic-service mailpieces, the Postal Service could not
    implement both the Manual changes and the noticed price
    increases without violating the price cap. 
    Id.
     at 35–36. The
    Commission therefore gave the Postal Service an option: it
    could either implement the Manual change as scheduled and
    resubmit proposed rates that fell within the price cap; or it
    could elect not to implement the Manual change and proceed
    with its noticed price changes. 
    Id. at 36
    . The Postal Service
    elected to delay the Manual change and implement its noticed
    price increases.
    This petition for review followed. The Postal Service
    argues that the plain language of the price cap statute and
    applicable regulations forbid the Commission from deeming
    changes to mail preparation requirements to be changes in
    rates. In addition, the Postal Service argues that the
    Commission’s decision is arbitrary and capricious because it
    fails to establish a clear and rational standard for which
    changes to mail preparation requirements it would consider
    17
    “changes in rates,” resulting in inconsistent application of the
    standard within the Commission’s decision. Finally, the
    Postal Service argues that the Commission’s decision is
    arbitrary and capricious because the Commission
    unreasonably refused to consider whether mailers will shift to
    using full-service Intelligent Mail.
    II. ANALYSIS
    “Because the Congress expressly delegated to the
    Commission responsibility to implement [the price cap
    statute], we review its interpretation” of that statute under the
    standards enunciated in Chevron and its progeny. USPS v.
    Postal Regulatory Comm’n, 
    640 F.3d 1263
    , 1266 (D.C. Cir.
    2011). Under Chevron’s First Step, if “Congress has directly
    spoken to the precise question at issue . . . , that is the end of
    the matter; for the court, as well as the agency, must give
    effect to the unambiguously expressed intent of Congress.”
    Chevron, 
    467 U.S. at
    842–43. If the statute is ambiguous,
    Chevron’s Second Step then requires us to consider whether
    the Commission has acted pursuant to delegated authority
    and, if so, whether its interpretation of the statute is
    “permissible.” 
    Id. at 843
    .
    Even if the statute is ambiguous and does not foreclose
    the Commission’s interpretation, however, the Commission’s
    exercise of its authority must be “reasonable and reasonably
    explained” in order to survive arbitrary and capricious review
    under the Administrative Procedure Act. Mfrs. Ry. Co. v.
    Surface Transp. Bd., 
    676 F.3d 1094
    , 1096 (D.C. Cir. 2012).
    Furthermore, we review the Commission’s interpretation of
    its own regulations with “substantial deference,” allowing that
    interpretation to control unless “plainly erroneous or
    inconsistent with the regulation.” Thomas Jefferson Univ. v.
    18
    Shalala, 
    512 U.S. 504
    , 512 (1994) (internal quotation marks
    omitted).
    At the heart of this case is the Commission’s
    interpretation of its statutory and regulatory price cap
    authority as extending beyond regulation of posted rates to
    allow regulation of Postal Service mail preparation
    requirements that may represent classification changes with
    “rate effects.” We hold that the statute and regulations are
    ambiguous and that, contrary to the Postal Service’s
    arguments, their “plain language” does not forbid regulation
    of mail preparation requirement changes with rate effects.
    We hold, however, that the Commission’s decision is
    arbitrary and capricious because it is not “reasonably
    explained.” Mfrs. Ry. Co., 676 F.3d at 1096. We therefore
    grant in part the petition for review and remand to the
    Commission to more clearly enunciate the standard it is using
    to determine which mail preparation requirement changes are
    “changes in rates,” and to consider again how that standard
    applies to the preparation requirement changes at issue in this
    case.
    A. The Statute and Regulations Are Ambiguous
    The Postal Service’s primary objection to the
    Commission’s Order is that the Commission lacks authority,
    under both the price cap statute and its implementing
    regulations, to consider mail preparation requirement changes
    in the Manual as “changes in rates” that count against the
    price cap. We disagree.
    The Postal Accountability and Enhancement Act’s price
    cap provision states that
    19
    [t]he system for regulating rates and classes for market-
    dominant products shall—
    (A) include an annual limitation on the percentage
    changes in rates to be set by the Postal Regulatory
    Commission that will be equal to the change in the
    Consumer Price Index for All Urban Consumers . . . over
    the most recent available 12-month period preceding the
    date the Postal Service files notice of its intention to
    increase rates[.]
    
    39 U.S.C. § 3622
    (d)(1)(A). Under this statute, the
    Commission’s authority extends only to regulate “changes in
    rates.” A related provision defines “rates” as including
    “fees for postal services.” 
    Id.
     § 102(7).
    The critical statutory question in this case is whether
    “changes in rates” encompasses only changes to the official
    posted prices of each product, as the Postal Service argues, or
    also changes to the prices actually applied to particular
    mailpieces, as the Commission argues. The language of the
    Act is ambiguous: “Changes in rates” is not specifically
    defined, and could apply either to the posted rates or the rates
    that customers actually pay. Neither interpretation conflicts
    with the statutory definition of “rates” as “fees for postal
    services,” since fees, like rates, can be both posted on a list
    and charged to specific mailpieces. See id. § 3622(d)(1)(A).
    The language of the statute therefore does not conflict with an
    interpretation of “changes in rates” as changes in the fees as
    applied to specific classifications of mailpieces.
    Moreover, nothing in the language or purpose of the
    statute renders unreasonable the Commission’s interpretation
    of “changes in rates” as extending to changes in the rates as
    they are applied to specific mailpieces. First, as noted, the
    language of the statute does not provide any relevant
    20
    limitation on the rates considered. Second, the Commission
    points out that the purpose of the price cap statute is to
    prevent the Postal Service from using its market-dominant
    power to charge customers unreasonably high prices. The
    Commission’s interpretation of the statute prevents the Postal
    Service from evading the price cap by shifting mailpieces to
    higher rates through manipulation of its mail preparation
    requirements. The Commission’s interpretation is therefore
    consistent with the price cap’s language and purpose, and the
    Commission’s delegated authority to administer the cap.
    The Postal Service’s arguments to the contrary are
    unavailing. Its plain language argument, as demonstrated
    above, simply does not fit the terms of the statute. The Postal
    Service attempts to bolster its reading of the statute by
    pointing out that the statute refers to “the Postal Service
    fil[ing] notice of its intention to increase rates.” Id. The Postal
    Service argues that this provision clarifies that “rates”
    therefore means only those rates for which the Postal Service
    must file notice. The Postal Service then argues that it is not
    required to file notice of its mail preparation requirement
    changes, and therefore “changes in rates” should not be
    considered to encompass mail preparation requirement
    changes. But this argument begs the question: If the
    Commission’s interpretation of the statute is correct, the
    Postal Service may, indeed, have to file a notice with the
    Commission when it makes certain mail preparation
    requirement changes that result in mailpieces being charged
    higher prices. That is in part the question at issue in this case.
    Therefore the “filing” language identified by the Postal
    Service clarifies no ambiguity about whether changes in rates
    encompass both changes to the posted rates and changes to
    rates brought about through the modification of the Postal
    Service’s classification system.
    21
    Nor are we convinced by the Postal Service’s observation
    that the Act sometimes distinguishes between “rates” and
    “classifications,” which the Postal Service argues requires the
    conclusion that a change in rates cannot be the same thing as a
    change in classification. See, e.g., id. § 3622(d)(1) (creating
    requirements for a system for regulating “rates and classes”).
    This argument ignores the fact that the Commission is not
    stating that changes in classifications are themselves changes
    in rates; rather, the Commission merely points out the self-
    evident fact that changes in classifications can cause changes
    in the rates experienced by mailers, a point the Postal Service
    does not dispute. It is those changes in rates paid by mailers
    that the Commission seeks to regulate, whether they occur
    through the posting of new prices to a list or through changes
    in classification.
    In short, the Postal Service has failed to show that
    “Congress has directly spoken to the precise question at
    issue,” Chevron, 
    467 U.S. at 842
    , or that Congress has
    precluded the Commission’s interpretation of the statute. The
    statute therefore leaves a gap to be filled by the Commission
    pursuant to its delegated authority to regulate rates and classes
    for market-dominant products.
    Nor can the Postal Service show that the Commission’s
    price cap authority over mail preparation changes is
    constrained by regulation. The regulations governing
    classification changes are also ambiguous as to whether they
    cover mail preparation requirement changes outside the Mail
    Classification Schedule. The relevant regulation reads,
    The Postal Service shall make reasonable adjustments to
    the billing determinants [i.e., volume levels] to account
    for the effects of classification changes such as the
    introduction, deletion, or redefinition of rate cells.
    22
    
    39 C.F.R. § 3010.23
    (d)(2). Nothing in the plain language of
    the regulation forbids the Commission from considering
    whether mail preparation requirement changes such as those
    in the Manual “redefine” a rate cell. As the Postal Service
    concedes, operational changes in the Manual can define and
    redefine the “eligibility” for a rate cell. The regulation is
    silent as to whether redefining the eligibility for a rate cell –
    in other words, defining which mailpieces can fit into that rate
    cell – is a redefinition of the rate cell itself. Certainly,
    however, the regulation does not foreclose the Commission’s
    interpretation, and we are bound to defer to that interpretation
    unless it is “plainly erroneous or inconsistent with the
    regulation.” Thomas Jefferson Univ., 
    512 U.S. at 512
     (internal
    quotation mark omitted).
    We are not convinced by either of the Postal Service’s
    arguments attempting to limit the scope of this regulation.
    First, the Postal Service argues that “classification changes”
    in the regulation refers only to changes made to the official
    Mail Classification Schedule (which establishes rates for mail
    services), not changes made to the Postal Service’s
    operational Manual (which sets mail preparation
    requirements). But nothing in the language of the regulation
    limits its scope to classification changes contained in the
    Schedule. On the other hand, changes in the Manual that
    reclassify a mailpiece from one product or rate cell to another
    fall comfortably within the plain meaning of the phrase
    “classification changes.”
    The Postal Service has provided no principled reason,
    originating in the statute or regulations, for why the price cap
    should treat classification changes in the Manual differently
    than classification changes in the Schedule when either
    change can cause a change in the rates paid by mailers. The
    23
    regulation is therefore ambiguous and does not preclude the
    Commission’s reasonable assertion of authority over some
    mail preparation requirement changes with rate effects.
    The Postal Service’s final argument regarding the
    interpretation of the regulation is that the Commission’s
    reading of “classification changes” as extending beyond the
    Mail Classification Schedule would wreak havoc with the
    Postal Service’s ratemaking by requiring it to count “[a]ny
    mail-preparation requirement” as a classification change that
    may change rates. Br. of U.S. Postal Serv. 41. The Postal
    Service is certainly correct that the implications of the
    Commission’s interpretation of its authority are potentially
    staggering. Nonetheless, this does not change the fact that, in
    regulating the price cap, the Commission has some authority
    to take account of operational rules that have rate effects. This
    does not mean that the Commission has unfettered authority.
    Any regulatory approach must be a product of reasoned
    decisionmaking. We now turn to this issue.
    B. The Commission’s           Decision     Is   Arbitrary    and
    Capricious
    As noted above, the statute and regulations do not
    foreclose the Commission’s claim that, in regulating the
    inflation-based price cap, it has some authority to assess mail
    preparation requirements that have rate effects. However, the
    Commission’s Order in this case fails under arbitrary and
    capricious review. “Put simply, the [Administrative Procedure
    Act] requires that an agency’s exercise of its statutory
    authority be reasonable and reasonably explained.” Mfrs. Ry.
    Co., 
    676 F.3d at 1096
    . The agency fails to reasonably explain
    its decision if it gives “differential treatment of seemingly like
    cases.” LePage’s 2000, Inc. v. Postal Regulatory Comm’n,
    
    642 F.3d 225
    , 232 (D.C. Cir. 2011). And we owe no
    24
    deference to an agency determination that is “largely
    incomprehensible.” Coburn v. McHugh, 
    679 F.3d 924
    , 926
    (D.C. Cir. 2012).
    At its core, the Commission’s Order is arbitrary and
    capricious because it fails to articulate a comprehensible
    standard for the circumstances in which a change to mail
    preparation requirements such as the one in this case will be
    considered a “change in rates.” The failing is particularly
    concerning because the Commission acknowledges that its
    interpretation of its authority could have broad consequences
    for the Postal Service, theoretically allowing the Commission
    to superintend not only the changes in posted rates listed in
    the Mail Classification Schedule, but also any of the myriad
    operational changes that reclassify mailpieces and have “rate
    effects.” The Commission does not claim this unbridled
    authority. Indeed, the Commission concedes that it has a
    responsibility to provide “clear guidance to the Postal Service
    and its customers about the scope and contours of the price
    cap requirements.” Order on Price Adjustments at 15. In
    response to the Postal Service’s concern that the
    Commission’s reasoning would lead it to deem all mail
    preparation requirements to be changes in rates, the
    Commission sought to reassure the Postal Service with these
    words: “The Commission has not and will not
    indiscriminately treat all new mail preparation requirements
    as rate adjustments.” Id. at 25. Unfortunately, the
    Commission’s decision fails to set forth a standard that will
    ensure that this promise is kept.
    In attempting to define which operational changes would
    count as rate adjustments, the Commission is cryptic, to say
    the least. It says that a change in rates occurs when the mail
    preparation requirement change at issue “require[s] mailers to
    alter a basic characteristic of a mailing in order for the
    25
    mailing to qualify for the same rate category for which it was
    eligible before the change in requirements.” Id. at 18. This
    purported standard does not come close to satisfying the
    requirement of reasoned decisionmaking, most notably
    because the reference to a “basic characteristic of a mailing”
    has no content and is not accompanied by an adequate
    explanation of how the standard applies to the facts of this
    case. As a consequence, the purported standard is
    indiscriminate and offers no meaningful guidance to the
    Postal Service or its customers on how to treat future changes
    to mail preparation requirements. Indeed, the Commission’s
    application of the standard in this case appears to be
    inconsistent and inadequately explained.
    In the same Order that determined that the revised
    Intelligent Mail requirements constituted “changes in rates,”
    the Commission considered whether another change in
    “preparation requirements constitute[d] a price change.”
    Order on Price Adjustments at 71. The second operational
    change involved the Postal Service’s rules for preparing flat-
    shaped mailpieces for shipment. Previously, the Postal
    Service had recommended that certain flat-shaped mailpieces
    be stacked in bundles of equal height so that they could more
    efficiently interact with the sequencing machines used by the
    Postal Service. In its notice of rate adjustment, however, the
    Postal Service proposed making the “bundling” rule
    mandatory for such flat-shaped mailpieces to qualify for
    certain rates. By making the “bundling” rule mandatory, the
    Commission acknowledged that “the new preparation
    requirements may result in some mailers paying higher
    prices” because those mailers who did not change their
    shipping methods would be forced into a higher rate cell. Id.
    Nevertheless, the Commission concluded that these
    operational changes do not count as changes in rates because
    26
    the requirements “do not change the basic characteristics of a
    mailing.” Id. This is hard to fathom.
    The Commission’s attempt to explain the differences
    between the bundling rule and the Intelligent Mail change
    does not withstand scrutiny. In considering the Intelligent
    Mail change, the Commission stated that the requirement
    “change[d] the basic characteristics of a mailing” because it
    “compel[led] mailers to change their mailing practices in
    order to qualify for the same rates they currently qualify for.”
    Id. at 30. This is precisely what the bundling rule requires.
    Yet the Commission ruled that the rate effects of the bundling
    rule do not count in assessing the inflation-based price cap.
    The Commission never satisfactorily explains why one
    change in mailing practices alters “a basic characteristic of a
    mailing” while the other does not. Nor is it obvious or
    intuitively clear why putting a barcode on a mailpiece is
    different from moving an address label or changing the
    bundling configuration of mailpieces, both of which the
    Commission has said would not constitute changes to a basic
    characteristic of mailpieces. Id. at 72.
    The Commission relies on a factually contested point that
    one change is greater in magnitude than the other, with
    barcoding requiring “significant” changes, id. at 29, while
    bundling requires “minor modifications,” id. at 72. But, even
    accepting this as true, it is unclear from the Commission’s
    decision why the size of the change determines the “type” of
    the change – i.e., why a small change that admittedly affects
    rates is not a “change in rates.” It is likewise unclear why the
    magnitude of the change determines whether the change
    affects “a basic characteristic of a mailing.”
    27
    The Commission’s brief to this court belatedly asserts
    that “trivial preparation changes are the most likely to have
    virtually universal adoption by mailers” and therefore may not
    actually change rates paid by mailers. Br. for the Postal
    Regulatory Comm’n 42. This claim is nowhere to be found in
    the Commission’s decision. Therefore, “whatever the merits
    of this position, we cannot consider it because the
    Commission did not set it forth below.” LePage’s 2000, Inc.,
    
    642 F.3d at 231
    . Furthermore, the assertion cannot be squared
    with the Commission’s rule that the Postal Service may not
    rely on forecasts of mailer behavior.
    Neither the Commission’s unelaborated “basic
    characteristic” standard nor its application here effectively
    explains the Commission’s reasoning or resolves the
    ambiguity about the treatment under the price cap of future
    mail preparation requirement changes. As the Commission
    itself has noted, indiscriminately treating mail preparation
    requirement changes as rate changes could have far-reaching
    and enormous consequences for the day-to-day and month-to-
    month operations of the Postal Service, including its ability to
    reasonably manage its own policies. While the Commission
    may well be able to determine a basis for treating the
    Intelligent Mail rule and the bundling rule differently, it has
    not enunciated that basis in this case or provided guidance for
    future cases. “At the least, the Commission must explain this
    differential treatment of seemingly like cases,” and “explain
    how it can read the same evidence differently when applied”
    to apparently similar changes. 
    Id. at 232
    .
    Although the Commission may have the authority under
    the price cap statute and regulations to consider mail
    preparation requirement changes of the kind at issue in this
    case as changes in rates, its decision here “must be remanded
    because of a basic inconsistency in its reasoning.” Air Line
    28
    Pilots Ass’n v. FAA, 
    3 F.3d 449
    , 453 (D.C. Cir. 1993). During
    oral argument, counsel for the Commission argued that the
    Commission’s decision is “rulemaking through adjudication,”
    as if to suggest that it is not subject to serious scrutiny. The
    case law surely does not support this view.
    [T]he arbitrary and capricious standard governs review of
    all proceedings that are subject to challenge under the
    APA. Thus, if an action is subject to review under the
    APA, it does not matter whether it is a formal or informal
    adjudication or a formal or informal rulemaking
    proceeding – all are subject to arbitrary and capricious
    review under Section 706(2)(A).
    EDWARDS, ELLIOTT, & LEVY, FEDERAL STANDARDS OF
    REVIEW 203 (2d ed. 2013) (citation omitted); see also
    Allentown Mack, 
    522 U.S. at 374
     (“[A]djudication is subject
    to the requirement of reasoned decisionmaking as well.”).
    We have previously remanded adjudications to the
    Commission when we have found “that the Commission acted
    within its statutory authority” but “the Commission’s
    explanatory gap [was] palpable” with respect to its
    “inconsistent” application of its rules or “the bounds of its
    authority.” USPS, 676 F.3d at 1106–08; see also LePage’s
    2000, Inc., 
    642 F.3d at 234
     (remanding to allow the
    Commission to explain the “inconsistencies in its order”);
    Checkosky v. SEC, 
    23 F.3d 452
    , 463 (D.C. Cir. 1994)
    (discussing the authority of courts to “remand to the agency
    for a more complete explanation of a troubling aspect of the
    agency’s decision” in an adjudication); Plumbers and
    Steamfitters Local 342 v. NLRB, 
    598 F.2d 216
    , 217 (D.C. Cir.
    1979) (“[W]e remand to the NLRB to clarify its decision.”).
    Given the noted deficiencies in the Commission’s decision in
    this case, we have no choice but to remand.
    29
    ****
    We find no merit in the Postal Service’s other arguments,
    including its objection to the Commission’s application of the
    historical-volume rule in this case, so we deny the petition for
    review with respect to these matters.
    III. CONCLUSION
    For the reasons given above, we deny the petition for
    review in part and grant in part. We hold that the price cap
    statute and the applicable regulations do not entirely foreclose
    the Commission from determining that some mail preparation
    requirements constitute “changes in rates.” We also hold,
    however, that the Commission's decision in this case is
    arbitrary and capricious for lack of reasoned decisionmaking.
    We therefore remand the case to the Commission to enunciate
    an intelligible standard and then reconsider its decision in
    light of that standard. Because the changes to the Manual
    should continue to be held in abeyance pending the outcome
    of the remand, it is unnecessary for us to vacate the
    Commission’s decision.
    So ordered.