A tariff action states the date from which it applies, and the operative event is almost always entry for consumption. Neither the date the goods were ordered nor the date they arrived decides the rate.
The operative event
Entry for consumption, or withdrawal from warehouse.
The standard formula is that an action applies to goods "entered for consumption, or withdrawn from warehouse for consumption, on or after 12:01 a.m. eastern time" on a stated date. Entry for consumption is the filing that releases goods into United States commerce. Goods can arrive under one rate and be entered under another.
Withdrawal from warehouse is included because goods in a bonded warehouse have arrived but have not been entered. The rate is the one in force when they are withdrawn.
In-transit exceptions
Stated per action, never assumed.
Some actions except goods already loaded onto a vessel and in transit on their final mode of transport before the effective date. Where that exception exists it is written into the action and given its own chapter 99 heading. It is not a general principle, and an action that does not state one does not have one.
Reading a rate for a past date
The layers in force then, not the layers in force now.
A rate for a past entry has to be resolved against the actions that were being collected on that date, including actions since retired. Validity is held as a half-open interval, so a superseding rate begins exactly where its predecessor ends, without a gap and without an overlap on which both would apply.
Related
Elsewhere on this site.
Tariff Watch