19 CFR § 159.21 - Quantity upon which duties based.
Insofar as duties are based upon the quantity of any merchandise, such duties shall be based upon the quantity of such merchandise at the time of its importation, except in the following cases:
(a) Manipulation in warehouse. If any merchandise covered by a warehouse entry has been cleaned, sorted, repacked, or otherwise changed in condition under section 562, Tariff Act of 1930, as amended (19 U.S.C. 1562), withdrawals shall be passed and the entry liquidated on the basis of the weight, gauge, or measure of such merchandise in its manipulated condition with an appropriate notation in the duty statement that the duties are assessed on the basis of the manipulated condition of the merchandise.
(b) Alcoholic beverages. Duties on certain alcoholic beverages are assessed only on the quantities entered or withdrawn for consumption (see § 159.4).
(c) Cigars, cigarettes, and cigarette papers and tubes. Although Customs duties on cigars, cigarettes, and cigarette papers and tubes are assessed on the quantities imported, the internal revenue taxes on such merchandise are assessed only on the quantities entered or withdrawn for consumption (see § 159.5).