19 U.S.C. § 1315: Effective date of rates of duty

any article released under an informal mail entry shall be subject to duty at the rate or rates in effect when the preparation of the entry is completed; any article which is not subject to a quantitative or tariff-rate quota and which is covered by an entry for immediate transportation made at the port of original importation under section 1552 of this title , if entered for consumption at the port designated by the consignee, or his agent, in such transportation entry without having been taken into the custody of the appropriate customs officer under section 1490 of this title , shall be subject to the rate or rates in effect when the transportation entry was accepted at the port of original importation; and any article for which duties may, under section 1505 of this title , be paid at a time later than the time of making entry shall be subject to the rate or rates in effect at the time of entry. Any article which has been entered for consumption but which, before release from custody of the Customs Service, is removed from the port or other place of intended release because of inaccessibility, overcarriage, strike, act of God, or unforeseen contingency, shall be subject to duty at the rate or rates in effect when the entry for consumption and any required duties were deposited in accordance with subsection (a) of this section, but only if the article is returned to such port or place within ninety days after the date of removal and the identity of the article as that covered by the entry is established in accordance with regulations prescribed by the Secretary of the Treasury. Insofar as duties are based upon the quantity of any merchandise, such duties shall, except as provided in chapter 98 of the Harmonized Tariff Schedule of the United States and section 1562 of this title (relating respectively to certain beverages and to manipulating warehouses), be levied and collected upon the quantity of such merchandise at the time of its importation. No administrative ruling resulting in the imposition of a higher rate of duty or charge than the Secretary of the Treasury shall find to have been applicable to imported merchandise under an established and uniform practice shall be effective with respect to articles entered for consumption or withdrawn from warehouse for consumption prior to the expiration of thirty days after the date of publication in the Federal Register of notice of such ruling; but this provision shall not apply with respect to the imposition of antidumping duties, or the imposition of countervailing duties under section 1303 of this title (as in effect on the day before the effective date of title II of the Uruguay Round Agreements Act) or section 1671 of this title . This subsection shall not apply with respect to increases in rates of duty resulting from the enactment of the Harmonized Tariff Schedule of the United States to replace the Tariff Schedules of the United States. The amendments made by this section [amending this section and sections 1303 and 1516 of this title] shall take effect on the date of the enactment of this Act [ Jan. 3, 1975 .] For purposes of applying the provisions of section 303(a)(4) of the Tariff Act of 1930 [ section 1303(a)(4) of this title ] (as amended by subsection (a)) with respect to any investigation which was initiated before the date of the enactment of this Act [ Jan. 3, 1975 ] under section 303 of such Act (as in effect before such date), such investigation shall be treated as having been initiated on the day after such date of enactment under section 303(a)(3)(B) of such Act.”