A post-summary correction for a refund: the window, the ACE status rules and when the money arrives

When is a PSC the right route for money back?

When an audit finds that a line on an entry was declared at more duty than the law required on its entry date, and the entry has not liquidated. Then the correction happens inside the entry: a post-summary correction replaces the entry summary, the entry liquidates at the lower amount, and the difference comes back with interest. No protest, no claim, no separate filing with its own review.

This page is the refund direction. The underpayment direction, where the PSC raises duty and the ACH payment rules since August 5, 2026 apply, is on a post-summary correction that increases duty. Once the entry has liquidated, the route is a protest; how to recover overpaid import duty maps every route by entry status.

How long is the window?

The PSC test, republished in full by CBP on July 6, 2026 (91 FR 41053), sets one rule and two exceptions.

ACE rejects a PSC outside the window automatically, CBP's PSC page says. CBP's normal liquidation cycle is 314 days (the figure CBP's page uses when it puts an entry "back into the 314-day liquidation cycle"), and 15 days before day 314 is day 299, so on an entry that liquidates on that cycle the 15-day limit falls one day before day 300. Treat day 299 as the last safe day unless you know the scheduled liquidation date is later. Count from the date of entry, which no PSC can change.

The extension row matters for refunds. If an audit is running and some entries are near day 300, an importer can ask for an extension of liquidation under 159.12 before filing, and CBP's business rules say the extension must be requested and approved before the PSC is filed. That trades a later refund for a refund at all.

Which ACE status rules decide whether the PSC is accepted?

The notice's section V and CBP's entry summary business rules set these status conditions on the entry summary, or on the last PSC filed against it.

Two practical consequences. First, a refund PSC on an entry whose earlier PSC raised duty waits until that increase is paid in full and processed: the notice blocks any subsequent PSC until then. If one entry carries both an underpaid and an overpaid line, file one PSC with both changes. Second, a PSC can be filed by a different filer than the one who filed the entry, if the importer of record authorizes it; CBP's business rules say ownership of the summary then moves to the new filer.

What can a refund PSC change, and what can it not?

A PSC can change any data element the notice does not list as fixed: classification, value, quantity, country of origin, duty, fees, ruling numbers, AD/CVD case data. Two items on the fixed list stop common refund claims:

• The 1520(d) trade-agreement indicator. A missed USMCA, Korea, Chile, Peru, Colombia, Panama, Oman or CAFTA-DR claim cannot be added by PSC. It goes through 19 U.S.C. 1520(d) within one year of importation, and 1505(c) runs interest only from the date of that claim. Unclaimed USMCA preference on past entries covers that route.
• The importer of record. If the wrong party was importer of record, CBP's page routes the change through CBP Form 3347 first, after which a PSC may correct the rest.

Agricultural fees are another limit: CBP's business rules say CBP does not refund them, but a PSC correcting the quantity is needed before the USDA Agricultural Marketing Service will.

Which reason codes go on a refund PSC?

Every PSC needs at least one reason code and a text explanation (91 FR 41053). CBP's PSC page allows up to five reason codes at header or line level, with further detail in the description. The codes are in the ACE CATAIR Entry Summary Create/Update chapter, AE Tables 14 and 15, September 2026 version. The line codes that carry most refunds:

Header changes have their own codes in AE Table 14, such as H13 for a header fee and H14 for a change from an AD/CVD entry type to a non-AD/CVD type. Where no code fits, H99 requires the reason to be spelled out in the explanation. Write the explanation from the audit finding: the line, the data element, the old and new values and why the new one is right on the entry date.

When does the money arrive?

Not when ACE accepts the PSC. A PSC is, in CBP's words, essentially a new entry summary, and it liquidates as any other summary does. 19 U.S.C. 1505(b) then requires refunds of excess deposits, with interest, within 30 days of liquidation. 1505(c) runs that interest from the date the estimated duties were deposited to the date of liquidation, at the quarterly IRS overpayment rate, which CBP publishes in the Federal Register.

Two things speed it up or hold it back:

• Accelerated liquidation. A filer can set an ABI indicator asking CBP to review the PSC and liquidate in the weekly cycle. CBP's PSC page and business rules say CBP processes those first and will strive to do so within 60 calendar days of receipt. It is an aim, not a deadline.
• Banking details. Since February 6, 2026, CBP issues refunds electronically (CBP Dec. 25-18, 91 FR 21). The importer, or the third party on a CBP Form 4811, needs an approved ACH Refund application in the ACE Portal, with a U.S. bank account. Without it the refund is rejected, and no delinquency interest runs for the delay.

Worked example: one overpaid line, two timelines

Illustrative figures, a corporate importer:

• Entry date June 4, 2026; estimated duties deposited June 18, 2026.
• Line 4: entered value $120,000, declared under an HTS number at 6.5 percent. A line-level audit on November 11, 2026 finds the goods belong under a number at 3.4 percent on the entry date. Overpayment: $120,000 x 3.1% = $3,720.
• Day 300 is March 31, 2027. The entry is scheduled to liquidate on April 16, 2027, so the 15-day cutoff is April 1 and day 300 governs.

The PSC goes in on November 23, 2026 with line reason code L03 and an explanation naming the line, the two numbers and the ruling relied on. The entry is on a paid statement, so it is in CBP control.

CBP's notice (91 FR 60141) lists corporate overpayment rates of 5 percent from April 1 to June 30, 2026 and 6 percent from July 1 to December 31, 2026; the 2027 rates are not yet published, so 6 percent is assumed here.

The accelerated path gets the money about three months sooner and earns about $51 less interest. For most importers the cash is worth more than the interest; for a large refund on an entry with other open questions, waiting may be worth it so that later findings can still go on a second PSC before liquidation. CBP computes interest under 26 U.S.C. 6621 and 6622, so its figure governs.

If the same audit had run in April 2027 instead, the window would have closed on March 31 and the $3,720 would come back only by protest after April 16, within 180 days.

How does a standing audit change refund PSCs?

The PSC window is the cheapest refund route there is, and it closes about two weeks before liquidation. An audit run once a year finds most overpayments after their windows closed; a monthly one finds them while a PSC is still possible. TariffSense reads entry summaries and broker entry exports, checks each line against the measures in force on its entry date and flags overpaid lines with the entry date, the line number and the data element that drives the difference, which is what the reason code and explanation need. The post-entry audit page shows the output. The PSC itself stays a filing for the importer and its broker.

What should you do next on your own entries?

1. Pull the open entries from your broker's export and compute day 300 for each. Sort by it.
2. Run the line checks in the post-entry audit pillar on the oldest first, and the duty calculator on any line where the rate on the entry date is in doubt.
3. For each overpaid line, note the reason code and the evidence (ruling, invoice, origin document) before handing it to the broker.
4. Check that each entry is on a paid statement, not under CBP review and not on a protest. If an entry is near day 300 and the finding is not ready, ask about an extension of liquidation first.
5. Confirm the ACH Refund application is approved in the ACE Portal. Decide per entry whether to request accelerated liquidation.
6. For entries already past the window, put the liquidation date plus 180 days in the calendar for a protest.

Confirm any filing with a licensed customs broker.