How do tariff schedule changes reach your entries, and how do you tell which entries a change touched?

Which document actually changes the duty on an entry?

Four documents carry a US tariff change, and only one of them is the law. The other three report it, explain it or program it, and each can arrive on a different day.

19 U.S.C. 3004(c)(1) treats the HTS as enacted, each statutory amendment and each presidential modification made under legal authority as "statutory provisions of law for all purposes". The USITC's role is described in 19 U.S.C. 3005(a): it "shall keep the Harmonized Tariff Schedule under continuous review" and recommend modifications to the President. In practice the USITC also publishes each revision, and its release list shows how often that happens: the 2026 Basic edition took effect December 31, 2025, and Revision 23 became current on November 10, 2026, which is 24 editions in just over ten months.

Why does the HTS revision lag behind the change?

Because the revision is compiled after the instrument is signed. Three recent changes show the gap, each dated from the instrument, the CSMS message and the USITC release list.

For July 24 to 27, 2026, the current edition of the schedule was Revision 12, which still carried heading 9903.03.01 and had no heading 9903.05.84. The law that applied to entries on those days rested on a presidential memorandum of July 23 and a USTR notice not printed until July 28; the only official filing text on those days was CBP's CSMS message, sent at 5:50 p.m. EDT on July 23, about six hours before the duties started. Anyone pricing entries from the published schedule on those days had the wrong stack, through no fault of the schedule.

The direction can also run the other way. An instrument can be printed weeks before it takes effect, and the next revision then carries the new heading with a future date in its text. Reading the date in the heading or note, not the revision date, is what keeps a lookup right.

How does one boundary change a real line?

Take a cotton knit T-shirt of Vietnam, subheading 6109.10.00 (General rate 16.5%), entered value $20,000, entered on two consecutive days.

Entered July 23, 2026. Heading 9903.03.01 applied to products of any country entered from 12:01 a.m. EST on February 24, 2026 through 12:01 a.m. EDT on July 24, 2026 (CSMS # 67844987), at "+ 10%" in Revision 12. Subheading 6109.10.00 is not on the U.S. note 2(aa) exemption lists, and the CAFTA-DR textile heading 9903.03.09 does not cover Vietnam.

Entered July 24, 2026. Revision 23 records that headings 9903.03.01 to 9903.03.11 "expired at the close of July 23, 2026". Heading 9903.05.84 covers products of Vietnam entered from 12:01 a.m. ET on July 24, 2026 at "+ 12.5%" (91 FR 47318), unless an exception heading such as the in-transit heading 9903.05.85 applies.

A shipment that arrived at midnight could fall either side, which is why the time of entry matters as much as the day. 19 CFR 141.68 sets that time by entry type, and the in-transit page covers the loading-date clauses that sometimes soften a boundary. The general method for a single line is in how to find the duty on an HTS code, and the duty calculator prices a code for any entry date.

How do you tell which of your entries a change reached?

Every change has three filters in it: a date window, a set of goods and a set of origins. Your entry lines carry all three, so the test is mechanical.

1. Read the instrument, not the summary. Note the start date and time, any end date, any in-transit clause, the Chapter 99 headings it creates or changes, the product list (by HTS number or description) and the countries.
2. Filter by entry date. Use the time of entry (block 7 of Form 7501), or the withdrawal date for warehouse withdrawals. Lines inside the window are candidates.
3. Filter by goods and origin. Match the 10-digit HTS numbers in column 33 and the country of origin against the instrument's lists.
4. Compare what was reported with what should have been. Each candidate line should carry the new heading, or an exception heading that explains why not. Lines outside the window should not.
5. Sort the differences by status. Unliquidated entries can be corrected by post-summary correction; liquidated ones by protest within 180 days of liquidation; underpayments that are material belong in a conversation about prior disclosure. How long you have to fix a past entry has the clocks side by side.

The lines most likely to be wrong are the ones filed in the first days after a change, before the revision and ACE programming caught up, like July 24 to 27, 2026, and the ones filed on the day a benefit started before its notice was printed, like November 30, 2025.

How do you track changes without reading every notice?

Subscribe to the three feeds and test each item against your own data.

• CSMS for filing instructions. Each message names the headings and dates.
• Federal Register for the instruments themselves: proclamations, executive orders, and USTR, Commerce and CBP notices. Its public inspection desk often shows a document a day or more before printing.
• USITC release list for each new revision, with its start date. A new revision is a prompt to look for headings that changed, not a sign that something took effect that day.

Then run each change through the filters above. Most changes touch none of your lines. The ones that do are found at line level, and the post-entry audit guide explains how to work through them. TariffSense keeps the measures by effective date and re-checks each entry line against the measures in force on its own entry date, so a change printed late or applied retroactively shows up as a per-line finding on the entries it reached. The audit page explains how to run that on your entry history, and the duty tools show the stack for a single code on either side of a change date. Confirm any correction or protest with a licensed customs broker.