United States v. Jerry Harris ( 2021 )


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  •                                In the
    United States Court of Appeals
    For the Seventh Circuit
    ____________________
    Nos. 20-1236 & 20-2234
    UNITED STATES OF AMERICA,
    Plaintiff-Appellee,
    v.
    DAVID GIBSON and JERRY HARRIS,
    Defendants-Appellants.
    ____________________
    Appeals from the United States District Court for the
    Northern District of Indiana, South Bend Division.
    No. 3:18-cr-33 — Jon E. DeGuilio, Judge.
    ____________________
    ARGUED JANUARY 21, 2021 — DECIDED APRIL 30, 2021
    ____________________
    Before SYKES, Chief Judge, and MANION and ST. EVE, Circuit
    Judges.
    ST. EVE, Circuit Judge. An informant gave South Bend po-
    lice the number to a phone that drug dealers in the South
    Bend area were supposedly using to sell drugs. To confirm
    this tip, officers carried out a series of controlled buys in
    which confidential informants or undercover officers called
    the number and followed instructions to buy heroin. Relying
    on the controlled buys, officers submitted an affidavit to a
    2                                        Nos. 20-1236 & 20-2234
    state court judge requesting an order for the phone’s service
    provider to share 30 days of precise, real-time GPS location
    data for the phone. The state court judge issued a “court or-
    der” granting the request. Relying on similar affidavits, offic-
    ers later obtained two more court orders authorizing an addi-
    tional 60 days of real-time tracking.
    The investigation ultimately led officers to two men at the
    top of the drug-trafficking conspiracy: David Gibson and
    Jerry Harris. Both defendants were federally indicted for con-
    spiring to distribute heroin. Before trial, the district court de-
    nied their motion to suppress evidence obtained through the
    cellphone tracking. The court treated the state court orders as
    valid search warrants for the tracking. At trial, officers and co-
    operators testified to the large-scale drug-trafficking scheme
    that the defendants had overseen. The jury ultimately con-
    victed both defendants of conspiring to distribute one kilo-
    gram or more of heroin. At sentencing, the district court found
    that the defendants had conspired to distribute a total of 10.5
    kilograms of heroin. The defendants now appeal the court’s
    denial of their motion to suppress. Harris also challenges the
    drug-quantity calculations at trial and sentencing, the court’s
    limits on his cross-examination of the cooperators at trial, and
    his sentence. We affirm the district court’s well-reasoned rul-
    ings across the board.
    I. Background
    A. The Investigation
    In late 2016 Ryan Williams was charged in Indiana state
    court for selling drugs. In March 2017, as an act of coopera-
    tion, Williams provided South Bend police the number to a
    phone (ending in -5822) that, he claimed, drug dealers in the
    Nos. 20-1236 & 20-2234                                           3
    South Bend area used to sell drugs. Over the next several
    months, officers made 28 controlled buys using the phone
    number. In these controlled buys, a confidential informant or
    undercover officer would call the number and follow instruc-
    tions to buy heroin. Each controlled buy involved half-gram
    increments of heroin. Different dealers, including Williams
    himself on occasion, would show up to deliver the drugs. The
    dealers would sell indiscriminately to anyone who called the
    number. At meeting spots, cars lined up to buy drugs.
    A few months into the investigation, officers sought to es-
    tablish surveillance of the phone’s location. In July 2017, offic-
    ers submitted an affidavit to an Indiana state court judge re-
    questing an order for Sprint, the phone’s service provider, to
    supply 30 days of precise, real-time GPS location data for the
    phone. The affidavit described two separate controlled buys
    in which a confidential informant had called the phone and
    met someone who sold him heroin. One of the controlled buys
    had occurred two and a half months earlier; the other had oc-
    curred the day before. The affidavit did not cite Federal Rule
    of Criminal Procedure 41 (which governs search warrants
    based on probable cause). Indeed, the affidavit did not men-
    tion probable cause at all. Instead, it cited federal statutes gov-
    erning the installation of mobile tracking devices, pen regis-
    ters, and trap and trace devices. See 
    18 U.S.C. §§ 3117
    , 3124.
    Based on the affidavit, an Indiana judge signed a “court
    order” finding probable cause to believe that the user of the
    -5822 phone had engaged in illegal drug possession and traf-
    ficking, and that precise tracking of the phone’s location
    would facilitate the user’s apprehension. Thus, the judge or-
    dered Sprint to supply 30 days of precise, real-time GPS loca-
    tion data for the phone. As authority for the order, the judge
    4                                       Nos. 20-1236 & 20-2234
    cited Rule 41, the Stored Communications Act, see 
    18 U.S.C. § 2703
    , and the federal statutes governing mobile tracking de-
    vices, pen registers, and trap and trace devices, see 
    18 U.S.C. §§ 3117
    , 3123, 3124. Per the order, Sprint gave officers 24-hour
    access to the phone’s precise location for 30 days.
    At the end of the 30-day period, officers submitted a sec-
    ond affidavit, requesting 30 more days of real-time cellphone
    tracking. The affidavit explained that, since obtaining the first
    court order, officers had carried out several more controlled
    buys using the same phone number. It described one of them
    in detail. The affidavit added that “this is a very complex or-
    ganization with approximately fifteen members who utilize
    the [phone] to facilitate drug trafficking.” In all other respects,
    the second affidavit mirrored the first. Based on the affidavit,
    the state court judge signed another order, essentially identi-
    cal to the first, authorizing 30 more days of real-time cell-
    phone tracking.
    The same series of events happened one more time. At the
    end of the second 30-day period, officers submitted a third af-
    fidavit, requesting 30 more days of GPS tracking data for the
    phone. This affidavit closely resembled the second one. It de-
    scribed in detail “one of several undercover officer buys”
    made in the previous 30-day period. The state court judge
    signed another materially identical order authorizing 30 more
    days of real-time cellphone tracking.
    Officers eventually recovered the -5822 phone in October
    2017 when they pulled over a man named Raymond Love for
    a traffic violation. Love had two “flip phones” on him, includ-
    ing the -5822 phone. Throughout the traffic stop, both phones
    rang nonstop.
    Nos. 20-1236 & 20-2234                                       5
    While tracking the -5822 phone, officers observed that it
    was located at various times in houses that they later con-
    nected to Gibson and Harris. Officers executed a search war-
    rant on the home associated with Harris, where they found a
    digital scale and almost $4,000 cash.
    B. Charges and Motion to Suppress
    A federal grand jury indicted Gibson and Harris with one
    count of conspiring to distribute more than one kilogram of
    heroin between March and October 2017. See 
    21 U.S.C. §§ 841
    (b)(1)(A), 846. Before trial, the defendants moved to
    suppress all evidence obtained through the phone tracking.
    They maintained that officers could not track the phone with-
    out a search warrant. Following a hearing, the district court
    denied the defendants’ motion to suppress. It ruled that the
    state court orders were valid warrants for the phone tracking.
    C. Trial
    The cases against Gibson and Harris were consolidated for
    trial. Various law enforcement officers testified, as did a few
    cooperating witnesses who had participated in the drug-traf-
    ficking conspiracy. Two of these cooperators were Williams
    and Loveless Daniel Naylor. Like Williams, Naylor was one
    of the street-level dealers who sold drugs directly to calling
    customers. Before the defendants went to trial, Williams pled
    guilty to conspiring to distribute one kilogram or more of her-
    oin. Naylor pled guilty to possession with intent to distribute
    heroin.
    Williams testified to the details of the drug-trafficking op-
    eration. Gibson ran the operation and Harris was his “right-
    hand man.” There were 20 to 25 dealers who worked in shifts.
    Gibson or Harris gave the dealers phones and “packs” of
    6                                      Nos. 20-1236 & 20-2234
    drugs to sell. The packs contained 22 to 24 individually pack-
    aged half-gram bags of heroin. A single dealer could go
    through as many as five or six packs on a weekend day. Most
    customers bought between one and ten half-gram bags at a
    time, but some bought up to fifteen. There were two phone
    numbers that customers could call: the -5822 number and an-
    other number ending in -9243. Williams testified that a trans-
    action required, at most, “probably about three” phone calls.
    An officer involved in the controlled buys testified that a suc-
    cessful buy generally required between one and four calls,
    though sometimes more were necessary. Naylor testified sim-
    ilarly regarding the details of the drug-trafficking operation.
    He added that, between March and October 2017, Gibson
    gave him between 600 and 700 grams of heroin to sell.
    Over Harris’s objection, the court forbade defense counsel
    from cross-examining the cooperating witnesses about the
    specific sentences they hoped to avoid by testifying for the
    government. The court explained that defense counsel could
    ask about mandatory minimums and “substantial sentences”
    but could not reference specific terms of imprisonment. Oth-
    erwise the jury might infer what sentences the defendants
    themselves would receive if convicted.
    The government introduced only 6.5 grams of heroin at
    trial. To prove the full quantity of drugs involved in the con-
    spiracy, the government called DEA Task Force Officer Joseph
    Focosi. Officer Focosi used two different formulas to calculate
    drug quantity. First, he relied on Williams’s testimony that he
    alone could sell up to six “packs” per day, with each pack con-
    taining 22 to 24 half-gram bags. Assuming that the dealers
    sold only one pack per day, and rounding the amount of her-
    oin in a pack down to 10 grams, Officer Focosi testified that
    Nos. 20-1236 & 20-2234                                           7
    the dealers would have sold 2.1 kilograms of heroin over a
    seven-month period (10 grams x 210 days = 2,100 grams). De-
    fense counsel did not object to this testimony.
    Officer Focosi’s second formula extrapolated drug quan-
    tity from phone calls. A DEA analyst had testified that, from
    the end of March 2017 through mid-October 2017, there were
    about 50,000 successful calls to the -5822 phone and 34,000
    successful calls to the -9243 phone. Conservatively estimating
    that each transaction involved six phone calls and half a gram
    of heroin, Officer Focosi testified that the conspiracy involved
    7 kilograms of heroin (84,000 total calls / 6 calls per transaction
    = 14,000 transactions x .5 grams per transaction = 7,000 grams).
    Harris’s counsel objected that the underlying testimony
    about calls per transaction had “not been that precise” and
    that Officer Focosi was offering an opinion based on his “ex-
    perience and expertise” in deciding what number of calls to
    use. The district court overruled the objection. The court ex-
    plained that whether six calls was a precise estimate went to
    the weight of the testimony, and that Officer Focosi was rely-
    ing on what he had learned from the investigation rather than
    “exercising any experience.”
    Defense counsel also objected to Officer Focosi’s assump-
    tion that all 84,000 calls were between dealers and customers,
    when “presumably, there would be calls between a dealer and
    other people as well.” The court overruled this objection, too,
    explaining: “I think that’s true, but that, again, goes to weight,
    and I think that’s something you can explore on cross exami-
    nation.”
    On cross-examination, Officer Focosi testified that he
    chose six calls per transaction because “it was more than one
    8                                        Nos. 20-1236 & 20-2234
    through four” (the range that witnesses had testified to). He
    admitted that he could have chosen a larger number, any-
    where from 5 to 24. He also admitted that he did not know the
    content of specific calls and conceded that some calls “might
    have had nothing to do with heroin deals.”
    The jury found both defendants guilty of conspiring to
    distribute one kilogram or more of heroin.
    D. Sentencings
    The probation officer calculated each defendant’s advi-
    sory Guideline range as 360 months to life. Both defendants
    had a criminal history category of VI, but Gibson’s offense
    level (38) was one point higher than Harris’s (37) because Gib-
    son was an “organizer or leader” of the drug-trafficking oper-
    ation whereas Harris was a “manager or supervisor.” See
    USSG § 3B1.1.
    Harris objected to the probation officer’s conclusion that
    he had conspired to distribute 10.5 kilograms of heroin. See
    USSG § 2D1.1(b)(18)(3) (increasing offense level for crimes in-
    volving 10 to 30 kilograms of heroin). To reach that number,
    the probation officer used Officer Focosi’s second formula
    from trial. Unlike Officer Focosi, however, the probation of-
    ficer assumed, based on the “most conservative” estimate at
    trial, that every drug sale required four, rather than six, calls
    (84,000 total calls / 4 calls per transaction = 21,000 transactions
    x .5 grams per transaction = 10,500 grams). Harris objected to
    this methodology as “speculative and not reasonable.” The
    court overruled his objection. It found, based on the evidence
    at trial, that the proposed drug-quantity calculation was
    “both certain and reasonable.” There was no evidence that
    any dealers had used the shared drug phones to make
    Nos. 20-1236 & 20-2234                                       9
    personal calls, and even if they had, the number of personal
    calls “would have to be dramatic to defeat the finding of ten
    or more kilograms” given how conservative the four-call and
    half-gram numbers were.
    The court sentenced both defendants well below the low
    end of the Guidelines range. Specifically, it sentenced Gibson
    to 240 months’ imprisonment and Harris to 262 months. The
    court explained the discrepancy at Harris’s sentencing. At 47,
    Gibson was a bit older than Harris, who was 38. Moreover,
    Gibson had recently received a 144-month consecutive sen-
    tence in another case for carrying a firearm in relation to a
    drug-trafficking crime. See 
    18 U.S.C. § 924
    (c). In the court’s
    view, Gibson’s older age and consecutive sentence influenced
    his risk of reoffending upon release. The same calculus did
    not apply to Harris, who was younger and not facing a con-
    secutive sentence. The court went on to determine that Harris
    warranted a three-level reduction, which corresponded to a
    sentencing range of 262 to 327 months. It found that “a sen-
    tence in this range will satisfy the purposes of the sentencing
    statute” and further “note[d] that even if I calculated the
    Guideline range differently in the first instance, I would vary
    to this same range based on my consideration of the 3553(a)
    factors as a whole.” A review of the § 3553(a) factors “per-
    suade[d] the Court that a sentence at the low end of the now
    revised recommended sentencing range is appropriate.” The
    defendants timely appealed.
    II. Discussion
    On appeal the defendants challenge the district court’s ad-
    mission of evidence obtained through the cellphone tracking.
    Harris also challenges the drug-quantity calculations at trial
    and sentencing, the district court’s limits on his cross-
    10                                       Nos. 20-1236 & 20-2234
    examination of cooperating witnesses, and the reasonable-
    ness of his sentence.
    A. Cellphone Tracking
    The defendants’ first contention is that officers violated the
    defendants’ Fourth Amendment rights by tracking the loca-
    tion of the -5822 phone without a warrant based on probable
    cause. They submit that the “court orders” authorizing the
    tracking were not valid warrants because they cited the Stored
    Communications Act, which requires a lesser showing than
    probable cause. See 
    18 U.S.C. § 2703
    (d) (requiring only “spe-
    cific and articulable facts showing that there are reasonable
    grounds to believe that the [information sought is] relevant
    and material to an ongoing criminal investigation”); see also
    United States v. Castro-Aguirre, 
    983 F.3d 927
    , 934 (7th Cir. 2020)
    (describing this standard as “significantly lower than the
    probable-cause requirement for a warrant”). They contend as
    well that the underlying affidavits did not supply probable
    cause for a search warrant.
    A Fourth Amendment “search” generally requires a war-
    rant based on probable cause. Carpenter v. United States, 
    138 S. Ct. 2206
    , 2221 (2018); Katz v. United States, 
    389 U.S. 347
    , 357
    (1967). The government does not dispute that the cellphone
    tracking in this case amounted to a “search” requiring a war-
    rant, and we assume for purposes of this appeal that it did.
    Nonetheless, the government maintains that the search was
    lawful because a valid warrant authorized it. The district
    court agreed and denied the defendants’ motion to suppress.
    We review the district court’s legal conclusions de novo and
    its factual findings for clear error. United States v. Jackson, 
    962 F.3d 353
    , 357 (7th Cir. 2020).
    Nos. 20-1236 & 20-2234                                       11
    A valid search warrant “require[s] only three things”: (1)
    an independent magistrate issuing it; (2) a showing of proba-
    ble cause “that the evidence sought will aid in a particular ap-
    prehension or conviction for a particular offense”; and (3) a
    particular description of “the things to be seized, as well as
    the place to be searched.” Dalia v. United States, 
    441 U.S. 238
    ,
    255 (1979) (internal quotations and citations omitted); accord
    United States v. Brewer, 
    915 F.3d 408
    , 414 (7th Cir. 2019). Sub-
    stance matters more than form in this context. Thus, a court
    order can satisfy the warrant requirement even if it is not la-
    beled a “warrant.” Dalia, 
    441 U.S. at 256
     (wiretap order was a
    valid warrant); United States v. Ning Wen, 
    477 F.3d 896
    , 898
    (7th Cir. 2007) (same). And a warrant that finds probable
    cause and cites Rule 41 satisfies the Fourth Amendment even
    if it also recites the lower standard of the Stored Communica-
    tions Act. United States v. Sanchez-Jara, 
    889 F.3d 418
    , 421 (7th
    Cir. 2018).
    The court orders in this case satisfy the requirements for a
    search warrant. First, the defendants do not contend, and
    there is no reason to believe, that the state court judge who
    issued the orders was anything but neutral and detached.
    Next, the orders cited Rule 41 and found probable cause to
    believe that the cellphone tracking would lead to the appre-
    hension of drug traffickers. Last, the orders particularly de-
    scribed the object of the search: the location of the -5822
    phone. With respect to the particularity requirement, we have
    held that “a warrant authorizing police to follow an identified
    phone, to see where it goes and what numbers it calls, partic-
    ularly describes the evidence to be acquired.” Sanchez-Jara,
    889 F.3d at 421; accord Brewer, 915 F.3d at 414 (“Judges must
    describe the specific person, phone, or vehicle to be tracked to
    satisfy the Fourth Amendment’s particularity requirement.”)
    12                                       Nos. 20-1236 & 20-2234
    (emphasis added). It makes no difference that the court orders
    were not labeled “warrants,” or that they cited, in addition to
    Rule 41, other statutes including the Stored Communications
    Act. See Dalia, 
    441 U.S. at 256
    ; Ning Wen, 
    477 F.3d at 898
    ;
    Sanchez-Jara, 889 F.3d at 421.
    We reject the defendants’ contention that the underlying
    affidavits did not supply probable cause. Probable cause for
    issuance of a search warrant exists if there is “a fair probabil-
    ity that contraband or evidence of a crime will be found in a
    particular place.” Illinois v. Gates, 
    462 U.S. 213
    , 238 (1983). The
    state court judge’s finding of probable cause “carries a strong
    presumption of correctness.” Sanchez-Jara, 889 F.3d at 421.
    Our task as “a reviewing court is simply to ensure that the
    [state court judge] had a substantial basis for concluding that
    probable cause existed.” Gates, 
    462 U.S. at
    238–39 (internal
    quotations, citation, and alterations omitted).
    We have held that a properly executed controlled buy is
    generally “a reliable indicator as to the presence of illegal
    drug activity.” United States v. Sidwell, 
    440 F.3d 865
    , 869 (7th
    Cir. 2006); see also United States v. Bacon, 
    991 F.3d 835
    , 839 (7th
    Cir. 2021) (“[C]ontrolled buys ordinarily go a long way to-
    ward establishing probable cause.”). Here, the affidavits de-
    scribed several controlled buys in detail, including the ar-
    rangement of the buys through calls to the -5822 phone. The
    first affidavit described two controlled buys involving the
    same confidential informant, whom officers searched, wired,
    and closely monitored. On two separate occasions, the confi-
    dential informant called the -5822 phone and successfully
    bought heroin, which he then turned over to the police. The
    second and third affidavits referenced the earlier orders and
    described additional, more recent controlled buys in which
    Nos. 20-1236 & 20-2234                                          13
    undercover officers called the same phone and bought heroin.
    We have little trouble concluding that these controlled buys
    gave the state court judge a substantial basis for a finding of
    probable cause to track the location of the phone sufficient to
    support each of its orders. See Gates, 
    462 U.S. at
    238–39.
    The defendants do not contest the method or execution of
    the controlled buys. Instead, they complain that one of the
    controlled buys in the first affidavit was two and a half
    months old. That is true, but the other controlled buy in the
    first affidavit took place the day before the state court judge
    signed the first order. So, to the extent that the first controlled
    buy might have been “stale,” the “more recent” controlled
    buy mitigated that issue by showing that “the same kind of
    criminal activity continued” through the present day. United
    States v. Rees, 
    957 F.3d 761
    , 769–70 (7th Cir. 2020).
    The defendants also suggest that the affidavits did not
    supply probable cause to track them, given that the affidavits
    did not mention them by name. But probable cause for a
    search warrant need not be tied to any particular person. See
    Gates, 
    462 U.S. at 238
     (requiring “a fair probability that con-
    traband or evidence of a crime will be found in a particular
    place”) (emphasis added); see also Bacon, 991 F.3d at 841. In this
    case, officers knew that the users of the -5822 phone were sell-
    ing drugs, but they did not know who the users were. That is
    why they wanted to track the phone—to apprehend the users
    for drug trafficking. In line with that mission, the state court
    judge found probable cause to believe that the cellphone
    tracking would facilitate the apprehension of drug traffickers.
    This finding was enough for probable cause, even though the
    judge did not identify Gibson or Harris by name. See Dalia,
    
    441 U.S. at 255
     (“[T]hose seeking the warrant must
    14                                      Nos. 20-1236 & 20-2234
    demonstrate to the magistrate their probable cause to believe
    that ‘the evidence sought will aid in a particular apprehension
    or conviction’ for a particular offense.” (quoting Warden, Md.
    Penitentiary v. Hayden, 
    387 U.S. 294
    , 307 (1967))).
    We therefore conclude that officers had a valid warrant to
    track the -5822 phone. The district court correctly denied the
    defendants’ motion to suppress. We need not address the gov-
    ernment’s alternative arguments that the good-faith excep-
    tion applies, see United States v. Leon, 
    468 U.S. 897
    , 922 (1984),
    and that the defendants lack “standing” to challenge the cell-
    phone tracking, see Byrd v. United States, 
    138 S. Ct. 1518
    , 1530
    (2018). We note, however, that an officer’s reliance on a war-
    rant presumptively establishes that the officer acted in good
    faith in carrying out a search. Leon, 
    468 U.S. at 922
    ; United
    States v. Lickers, 
    928 F.3d 609
    , 618 (7th Cir. 2019). Moreover,
    we are skeptical that either defendant has standing to chal-
    lenge the cellphone tracking. There was no evidence at the
    suppression hearing that either defendant personally pos-
    sessed or used the -5822 phone during the 90-day tracking pe-
    riod. The defendants maintain that the government conceded
    the defendants’ possession of the phone. But even if that is
    true, the evidence from trial suggests that the defendants had,
    at most, on-and-off possession of this cellphone that approxi-
    mately two dozen drug dealers shared to sell drugs. And
    there is no evidence that either defendant ever used the phone
    for personal, rather than commercial, purposes. Just as drug
    dealers who briefly occupy stash houses while packaging
    drugs lack a legitimate expectation of privacy in the stash
    houses, the defendants here would seem to lack a legitimate
    expectation of privacy in the whereabouts of a shared drug
    phone. See Minnesota v. Carter, 
    525 U.S. 83
    , 90–91 (1998); United
    States v. Gray, 
    491 F.3d 138
    , 147 (4th Cir. 2007); H. Hunter
    Nos. 20-1236 & 20-2234                                         15
    Bruton, Note, The Shifting Nature of Stash-House Standing and
    Sentencing, 
    42 N.Y.U. Rev. L. & Soc. Change 351
    , 358 (2018).
    Ultimately, we need not resolve this issue. And given the par-
    ties’ dispute as to whether the government conceded the de-
    fendants’ possession of the phone, it is best to leave it for an-
    other day.
    B. Drug-Quantity Calculations
    Apart from the cellphone tracking, Harris takes issue with
    the drug-quantity calculations at trial and at his sentencing.
    1. Trial
    Harris submits that Officer Focosi’s trial testimony was
    unreliable and ran afoul of the rules governing expert testi-
    mony. See Fed. R. Evid. 702; Fed. R. Crim. P. 16(a)(1)(G); see
    also United States v. Gaytan, 
    649 F.3d 573
    , 582 (7th Cir. 2011).
    As such, he challenges the sufficiency of the drug-quantity ev-
    idence and seeks to overturn the jury’s finding that he con-
    spired to distribute at least one kilogram of heroin. See 
    21 U.S.C. § 841
    (b)(1)(A) (providing a mandatory-minimum sen-
    tence for offenses involving one kilogram or more of heroin).
    Harris did not move for a judgment of acquittal, so we re-
    view the jury’s drug-quantity determination only for a “man-
    ifest miscarriage of justice.” United States v. Chaparro, 
    956 F.3d 462
    , 468 (7th Cir. 2020) (internal quotations and citation omit-
    ted). This means that the jury’s verdict stands unless “the rec-
    ord is devoid of evidence pointing to guilt, or … the evidence
    on a key element of the offense was so tenuous that a convic-
    tion would be shocking.” 
    Id.
     (internal quotations and citation
    omitted).
    Harris’s challenge to the jury’s drug-quantity determina-
    tion goes nowhere because the government offered the jury
    16                                        Nos. 20-1236 & 20-2234
    two independent ways to find that Harris conspired to dis-
    tribute more than one kilogram of heroin and Harris chal-
    lenges only one of these methods. First, Officer Focosi testi-
    fied, based on Williams’s testimony that he could sell up to
    six “packs” of heroin on a weekend day, the conspiracy in-
    volved 2.1 kilograms of heroin. To reach that number, Officer
    Focosi conservatively estimated that the dealers sold only one
    10-gram pack per day during the seven-month conspiracy (10
    grams x 210 days = 2,100 grams). Officer Focosi’s second for-
    mula extrapolated drug quantity from phone calls. A DEA an-
    alyst had testified that there were about 84,000 successful calls
    to the two drug phones during the conspiracy. Conservatively
    estimating that each transaction involved six phone calls and
    half a gram of heroin, Officer Focosi testified that the conspir-
    acy involved 7 kilograms of heroin (84,000 total calls / 6 calls
    per transaction = 14,000 transactions x .5 grams per transac-
    tion = 7,000 grams). Harris claims that Officer Focosi’s second
    formula was inadmissible expert testimony that the govern-
    ment failed to timely disclose. But even if that is true, Harris
    has never challenged Officer Focosi’s first formula. Officer
    Focosi’s first formula independently sustains the jury’s drug-
    quantity finding and renders harmless any error in the district
    court’s admission of Officer Focosi’s second formula. See Fed.
    R. Crim. P. 52(a); United States v. Jett, 
    908 F.3d 252
    , 265 (7th Cir.
    2018). Thus, Harris has not identified a prejudicial error in the
    drug-quantity calculation at trial—much less a manifest mis-
    carriage of justice. Chaparro, 956 F.3d at 468.
    2. Sentencing
    Harris also challenges the district court’s calculation of the
    drug quantity at sentencing. Whereas the government asked
    the jury to find that Harris conspired to distribute one
    Nos. 20-1236 & 20-2234                                          17
    kilogram or more of heroin, at sentencing the district court
    had to calculate the actual amount of heroin involved in the
    conspiracy and reasonably foreseeable to Harris. See USSG
    § 2D1.1, comment. (n.5); USSG § 1B1.3(a)(1)(B). Relying on the
    probation officer’s recommendations and the evidence at trial,
    the court found that the government had established by a pre-
    ponderance of the evidence that Harris conspired to distrib-
    ute 10.5 kilograms of heroin. The court reached this number
    by applying Officer Focosi’s second formula and assuming
    that each drug transaction required four, rather than six, calls
    (84,000 total calls / 4 calls per transaction = 21,000 transactions
    x .5 grams per transaction = 10,500 grams). Harris maintains
    that this calculation rested on speculative and unreliable data.
    More specifically, he claims that 4 calls per transaction is an
    arbitrary estimate, and that there is no evidence that all 84,000
    calls were drug related.
    A defendant attacking a district court’s factual findings at
    sentencing has “a steep hill to climb.” United States v. Ranjel,
    
    872 F.3d 815
    , 818 (7th Cir. 2017). We “will not disturb a sen-
    tencing court’s factual findings unless they are clearly errone-
    ous.” 
    Id.
     The government must prove drug quantity by a pre-
    ponderance of the evidence. United States v. Medina, 
    728 F.3d 701
    , 705 (7th Cir. 2013).
    The Sentencing Guidelines tie a defendant’s offense level
    to the quantity of drugs involved in the offense. See USSG
    § 2D1.1(c). In a drug conspiracy, “each conspirator is respon-
    sible for both the drug quantities directly attributable to him
    and amounts involved in reasonably foreseeable dealings by
    co-conspirators.” United States v. Austin, 
    806 F.3d 425
    , 431 (7th
    Cir. 2015); see USSG § 1B1.3(a)(1)(B). If the quantity of drugs
    seized “does not reflect the scale of the offense,” a court must
    18                                       Nos. 20-1236 & 20-2234
    “approximate” the total drug quantity. USSG § 2D1.1, com-
    ment. (n.5). To make such an approximation, the court “may
    consider, for example, the price generally obtained for the
    controlled substance, financial or other records, similar trans-
    actions in controlled substances by the defendant, and the size
    or capability of any laboratory involved.” Id.
    Drug-quantity calculations are “not an exact science.”
    United States v. Sewell, 
    780 F.3d 839
    , 849 (7th Cir. 2015). “De-
    termining drug quantities under the Sentencing Guidelines is
    often difficult, and district courts may make reasonable
    though imprecise estimates based on information that has in-
    dicia of reliability.” United States v. Bozovich, 
    782 F.3d 814
    , 818
    (7th Cir. 2015). The Guidelines do not permit “‘nebulous eye-
    balling,’” but “some amount of reasoned ‘speculation and rea-
    sonable estimation’” is permissible. United States v. Hollins,
    
    498 F.3d 622
    , 631 (7th Cir. 2007) (quoting United States v. Jar-
    rett, 
    133 F.3d 519
    , 530 (7th Cir. 1998)).
    Here, the district court properly relied on the evidence in
    the record to conservatively calculate the drug quantity. Its
    calculation was not clear error. All three numbers that the
    court plugged into Officer Focosi’s second formula (84,000 to-
    tal calls / 4 calls per transaction = 21,000 transactions x .5
    grams per transaction = 10,500 grams) had a firm basis in the
    record. Harris does not challenge the half-gram-per-transac-
    tion figure, nor could he. Williams, Naylor, and an officer in-
    volved in the controlled buys testified that the heroin was pre-
    packaged and sold in half-gram increments. Most customers
    bought between one and ten half-gram bags at a time, though
    some bought as many as fifteen. One half-gram bag per trans-
    action was thus an extremely conservative estimate.
    Nos. 20-1236 & 20-2234                                         19
    Harris describes the four-calls-per-transaction estimate as
    arbitrary. But Williams, who regularly sold heroin to buyers
    who called the drug phones, testified that the transactions re-
    quired, at most, three calls. Further, an officer who partici-
    pated in the controlled buys testified that the transactions
    usually required between one and four calls. Given this evi-
    dence, the four-call estimate was reliable and indeed very
    conservative. Harris counters that the discrepancy between
    the calls-per-transaction figure at trial (six calls) and sentenc-
    ing (four calls) demonstrates the arbitrariness of both num-
    bers. But at trial, the government sought to prove a minimum
    drug quantity beyond a reasonable doubt. See 
    21 U.S.C. § 841
    (b)(1)(A) (providing a mandatory-minimum sentence for
    offenses involving one kilogram or more of heroin); see also
    Alleyne v. United States, 
    570 U.S. 99
    , 103 (2013) (holding any
    fact that increases the penalty for a crime must be proven to a
    jury beyond a reasonable doubt). The actual quantity of drugs
    was not an element of the offense. See United States v. Abdulahi,
    
    523 F.3d 757
    , 760 (7th Cir. 2008). At sentencing, by contrast,
    the government sought to prove the actual drug quantity by
    a preponderance of the evidence. See 
    id.
     at 760–61. Given the
    different burdens of proof and required showings, there was
    nothing inconsistent about using different estimates of calls
    per transaction at trial and sentencing.
    Harris directs most of his criticism to the third figure—
    84,000 total calls. But this number, too, had a firm basis in the
    record. A DEA analyst reviewed phone records and testified
    that there were 84,000 successful calls to the two drug phones
    during the conspiracy. Harris insists that any number of these
    calls could have been unrelated to drugs. And to be sure, Of-
    ficer Focosi conceded at trial that he could not rule out the
    possibility that some of the calls were unrelated to drug
    20                                     Nos. 20-1236 & 20-2234
    transactions. But, as the district court recognized, there is no
    evidentiary support for Harris’s speculative hypothesis that
    the two dozen drug dealers who shared the drug phones were
    also receiving personal calls on the phones. All evidence
    points to the opposite conclusion—these were drug phones
    that on-duty dealers used to continuously make drug sales.
    When Williams was asked at trial who called the phones, he
    responded, “people who wanted to buy drugs.” Naylor testi-
    fied that “customers” called the phones. The government had
    to prove drug quantity by a preponderance of the evidence—
    not to an absolute certainty. On these facts, the district court
    did not err in calculating the heroin quantity.
    Harris relies heavily on United States v. Howard, 
    80 F.3d 1194
     (7th Cir. 1996). But the problem in Howard was the pro-
    bation officer’s failure to explain the evidentiary basis for the
    drug-quantity calculation. As we said: “Where either the pro-
    bation officer or the prosecution offers an estimate of the drug
    quantities for which the defendant should be held responsi-
    ble, the defendant ought to be on notice of all assumptions,
    rationale, and methodology underlying the calculation.” 
    Id. at 1204
    . Here, the government’s methodology was transparent.
    It derived from specific testimony that the government of-
    fered at trial. Harris tested the reliability of that testimony
    through cross-examination. Indeed, he bases his challenge to
    the court’s drug-quantity calculation primarily on conces-
    sions that he obtained from Officer Focosi at trial. Unlike the
    defendant in Howard, Harris could, and did, challenge the
    government’s methodology because he knew the evidentiary
    basis for it. A disputed evidentiary basis is not the same thing
    as no evidentiary basis. This distinction renders Harris’s out-
    of-circuit citations equally inapposite. See United States v.
    Sepulveda, 
    15 F.3d 1161
    , 1198 (1st Cir. 1993); United States v.
    Nos. 20-1236 & 20-2234                                         21
    Shonubi, 
    998 F.2d 84
    , 90 (2d Cir. 1993); United States v. Collado,
    
    975 F.2d 985
    , 998 (3d Cir. 1992).
    Harris also complains that the government’s use of phone
    calls to extrapolate drug quantity was unprecedented. That is
    not entirely true, as other circuits have upheld drug-quantity
    calculations extrapolated, at least in part, from phone calls.
    See, e.g., United States v. Green, 
    40 F.3d 1167
    , 1175 (11th Cir.
    1994). More importantly, though, the district court’s job was
    to make a reasonable estimate of drug quantity on the record
    before it. Austin, 806 F.3d at 431. This was a unique case. The
    evidence showed that Gibson and Harris oversaw a large
    drug-trafficking operation in which approximately two dozen
    drug dealers sold drugs indiscriminately to anyone who
    called either of two shared drug phones. The court had to ap-
    proximate the quantity of drugs involved in this conspiracy,
    and it did so reasonably. Nothing required the court to locate
    a prior case approving of its methodology for calculating
    drug quantity.
    For these reasons, the district court did not clearly err in
    calculating the drug quantity at Harris’s sentencing. And
    even if it did, any error was harmless. At Harris’s sentencing,
    the court said on the record that, even if it had calculated the
    Guidelines range differently, it would vary to the same range
    and impose the same sentence based on its independent con-
    sideration of the sentencing factors under 
    18 U.S.C. § 3553
    (a).
    When a sentencing court bases its sentence on the § 3553(a)
    factors and says it would have imposed the same sentence re-
    gardless of the Guidelines range, an error in calculating the
    Guidelines range may be harmless. See, e.g., United States v.
    Snyder, 
    865 F.3d 490
    , 500–01 (7th Cir. 2017); Molina-Martinez v.
    United States, 
    136 S. Ct. 1338
    , 1346–47 (2016). That happened
    22                                      Nos. 20-1236 & 20-2234
    here. The district judge presided over the trial and knew the
    facts of the conspiracy inside and out. He thoroughly ex-
    plained his sentence and anchored it in the § 3553(a) factors.
    Even if his drug-quantity calculation was wrong, the district
    judge knew the scale of the conspiracy and Harris’s role in it.
    He explained that he would have imposed the same sentence
    regardless of the Guidelines range. On these facts, any error
    in calculating drug quantity was harmless.
    C. Cross-Examination of Cooperators
    Harris argues next that the district court improperly con-
    strained his cross-examination of cooperating witnesses. He
    says he should have been allowed to question Williams and
    Naylor about the specific sentences they hoped to avoid by
    testifying for the government.
    The Sixth Amendment guarantees a criminal defendant
    the opportunity to effectively cross-examine witnesses
    against him. United States v. Trent, 
    863 F.3d 699
    , 704 (7th Cir.
    2017). But this right is not absolute: “a district court has dis-
    cretion to place reasonable limits on cross-examination, espe-
    cially when necessary to prevent irrelevant or confusing evi-
    dence from being presented to the jury.” 
    Id.
     Such irrelevant or
    confusing evidence includes “information from which [the
    jury] could infer defendants’ potential sentences.” 
    Id. at 705
    .
    Federal juries do not decide sentences in noncapital cases,
    so specific sentencing information “might confuse or mislead
    the juries in their true task: deciding defendants’ guilt or in-
    nocence.” 
    Id.
     The risk is that “the reality of a serious sentence
    could prejudice the jury and cause it to acquit the defendants
    of crimes they actually committed.” United States v. Hunter,
    
    932 F.3d 610
    , 619 (7th Cir. 2019). For these reasons, we have
    Nos. 20-1236 & 20-2234                                         23
    held that district courts may in some circumstances bar de-
    fense counsel from cross-examining cooperating witnesses
    about “the exact length” of the witness’s potential sentence.
    Trent, 863 F.3d at 706; Hunter, 932 F.3d at 620.
    Our standard for reviewing a district court’s limit on
    cross-examination “depends on whether the court’s limit ‘di-
    rectly implicates the core values of the Confrontation
    Clause.’” Trent, 863 F.3d at 704 (quoting United States v. Re-
    cendiz, 
    557 F.3d 511
    , 530 (7th Cir. 2009)). If it does, our review
    is de novo; if it does not, we review for abuse of discretion. 
    Id.
    The core values of the Confrontation Clause include allowing
    the defendant “to expose a witness’s motivation for testifying,
    his bias, or his possible incentives to lie.” Id. at 705 (quoting
    Recendiz, 
    557 F.3d at 530
    ). “But that value is only offended
    when ‘the defense is completely forbidden from exposing the
    witness’s bias.’” 
    Id.
     (quoting United States v. Sanders, 
    708 F.3d 976
    , 990 (7th Cir. 2013)). When the defense has “a reasonable
    opportunity to question witnesses about their biases, the Sixth
    Amendment is not implicated.” 
    Id.
    The district court’s limits on Harris’s cross-examination of
    Williams and Naylor did not implicate the core values of the
    Sixth Amendment. The court imposed a limited restriction on
    Harris’s cross-examination. It only forbade Harris from ques-
    tioning Williams and Naylor about the exact sentences they
    hoped to avoid. It otherwise gave Harris free reign to ask the
    witnesses about mandatory minimums and “substantial sen-
    tences.” See Trent, 863 F.3d at 705–06.
    And Harris took full advantage. Williams testified on
    cross-examination that, although he was a felon with two
    guns on him at the time of his arrest, the government never
    charged him with being a felon in possession of a firearm. See
    24                                      Nos. 20-1236 & 20-2234
    
    18 U.S.C. § 922
    (g)(1). The government also never charged him
    with carrying a firearm in relation to a drug-trafficking
    crime—an offense that, he admitted, carried “a substantial
    mandatory minimum.” See 
    18 U.S.C. § 924
    (c). Williams fur-
    ther conceded that he was testifying for the government to get
    his “time cut” on the charge that he pled guilty to—conspir-
    acy to distribute at least a kilogram of heroin—which carried
    “substantial penalties” and a “substantial mandatory mini-
    mum.” On top of that, Williams admitted that the government
    never filed a sentencing enhancement against him even
    though he had two qualifying prior convictions. See 
    21 U.S.C. § 851
    .
    For his part, Naylor testified on cross-examination that the
    government agreed to dismiss a § 924(c) count against him
    carrying a “substantial mandatory minimum.” The govern-
    ment also agreed not to file an applicable sentencing enhance-
    ment on the charge that Naylor pled guilty to—possession
    with intent to distribute heroin—which would have resulted
    in “even longer punishment in prison.” Naylor added that he
    was hoping to receive “a further sentence reduction” for tes-
    tifying against the defendants. He understood that the gov-
    ernment could move for such a reduction based on its evalu-
    ation of his trial testimony.
    This testimony shows that Harris could, and did, question
    the cooperators at length about their potential biases and mo-
    tives to lie. As such, we review for abuse of discretion. Trent,
    863 F.3d at 704. To decide if the court abused its discretion, we
    ask “whether the jury had sufficient information to make a
    discriminating appraisal of the witness’s motives and biases.”
    Id. at 706 (quoting Sanders, 708 F.3d at 991). The district court
    gave Harris wide latitude to cross-examine the cooperators
    Nos. 20-1236 & 20-2234                                          25
    about everything except the exact sentences they hoped to
    avoid by testifying for the government. As set forth above,
    Harris thoroughly probed the cooperators’ biases and mo-
    tives to lie. Both witnesses admitted that they faced significant
    sentences that they hoped the government would ask the
    court to reduce in light of their testimony. As in Trent, the
    court “did not err, let alone abuse its discretion,” in keeping
    the cooperators exact sentences off limits. Id.
    Harris counters that Trent and Hunter should not apply
    here because Williams and Naylor were not codefendants in
    the defendants’ case. But what matters under Trent and
    Hunter is that the jury might infer the defendants’ potential
    sentences from the cooperators’ potential sentences. See Trent,
    863 F.3d at 705; Hunter, 932 F.3d at 619. Here, Williams was
    charged separately, but he faced the same exact charge as the
    defendants: conspiracy to distribute at least a kilogram of her-
    oin. See 
    21 U.S.C. §§ 841
    (b)(1)(a), 846. Indeed, the district court
    instructed the jury that Williams “was involved in and has
    pled guilty to charges relating to the crime the defendants are
    charged with committing.” Given the identical nature of Wil-
    liams’s charges and the defendants’ charges, the court was
    well within its discretion to limit Harris’s cross-examination
    of Williams.
    Naylor, on the other hand, pled guilty to possession with
    intent to distribute heroin, see 
    21 U.S.C. § 841
    (a)(1), a different
    crime corresponding to a lower mandatory minimum. The
    district court acknowledged this difference, but explained its
    decision to nonetheless limit Harris’s cross-examination of
    Naylor:
    While it’s not the exact same charge, it is under the
    same statute. I believe the offense to which he pled
    26                                       Nos. 20-1236 & 20-2234
    guilty to constitutes one of the lesser includeds that the
    Court intends to give, and the plea agreement does, in
    fact, state that there’s a mandatory minimum of five
    years, which I think would give some insight into what
    these defendants might be looking at if convicted of
    these charges.
    The court carefully and permissibly exercised its discre-
    tion. We acknowledge, as we did in Hunter, that sharing spe-
    cific sentencing information with the jury is of concern when
    the cooperators and defendants face the same or similar
    charges. Hunter, 932 F.3d at 619. Here, though, the court rea-
    sonably concluded that the charge to which Naylor pled
    guilty was similar enough to the defendants’ charges that the
    jury might try to “deduce or infer the sentences facing the
    similarly-charged defendants” from information about
    Naylor’s sentence. Id. On these facts, we see no abuse of dis-
    cretion.
    We thus affirm the district court’s limits on Harris’s cross-
    examination of Williams and Naylor. Harris’s only other ar-
    gument on this score is a perfunctory and conclusory plea for
    us to overrule Trent and Hunter. This argument is waived.
    Puffer v. Allstate Ins. Co., 
    675 F.3d 709
    , 718 (7th Cir. 2012)
    (“[E]ven arguments that have been raised may still be waived
    on appeal if they are underdeveloped, conclusory, or unsup-
    ported by law.”).
    D. Harris’s Sentence
    Finally, Harris argues that his sentence of 262 months’ im-
    prisonment is substantively unreasonable because it is 22
    months longer than Gibson’s, even though Gibson was an
    “organizer or leader” of the drug-trafficking scheme whereas
    Nos. 20-1236 & 20-2234                                        27
    Harris was only a “manager or supervisor.” See USSG § 3B1.1
    (requiring a four-level enhancement for organizers or leaders
    and a three-level enhancement for managers or supervisors).
    We review the reasonableness of a sentence for abuse of
    discretion. Castro-Aguirre, 983 F.3d at 943. A below-Guide-
    lines sentence is presumptively reasonable. Id. at 944. “In-
    deed, we have never ‘deemed a below-range sentence to be
    unreasonably high.’” Id. (quoting United States v. Brown, 
    932 F.3d 1011
    , 1019 (7th Cir. 2019)).
    The district court did not abuse its discretion in sentencing
    Harris to 262 months’ imprisonment—a sentence that fell
    nearly 100 months below the low end of the advisory Guide-
    lines range of 360 months to life. As Harris points out, the dis-
    trict court had to consider, among other sentencing factors,
    “the need to avoid unwarranted sentence disparities among
    defendants with similar records who have been found guilty
    of similar conduct.” 
    18 U.S.C. § 3553
    (a)(6). And it did so. At
    Harris’s sentencing, the court expressly considered the need
    to avoid an unwarranted sentencing disparity between Harris
    and Gibson, who had similar roles in the conspiracy and iden-
    tical Guidelines ranges. The court explained, however, why a
    sentencing disparity between Gibson and Harris was not, in
    fact, “unwarranted.” At 47, Gibson was nine years older than
    Harris. Gibson was also serving a 12-year consecutive sen-
    tence for a § 924(c) conviction in another jurisdiction. Those
    factors influenced Gibson’s likelihood of reoffending upon re-
    lease, which is another sentencing factor. See § 3553(a)(2)(C);
    see also Dean v. United States, 
    137 S. Ct. 1170
    , 1176 (2017). The
    same recidivism calculus did not apply to Harris, who was
    younger and not facing a long consecutive sentence in another
    case.
    28                                      Nos. 20-1236 & 20-2234
    A district court has broad discretion to balance the
    § 3553(a) factors. United States v. Warner, 
    792 F.3d 847
    , 855 (7th
    Cir. 2015). The court’s reasoned decision to give Harris 22
    months more than Gibson was well within the range of rea-
    sonable sentences.
    III. Conclusion
    For these reasons, we affirm the defendants’ convictions
    and sentences.