19 U.S.C. § 2119 — Staging requirements and rounding authority

(a) Maximum aggregate reductions in rates of duty Except as otherwise provided in this section, the aggregate reduction in the rate of duty on any article which is in effect on any day under a trade agreement under section 2111 of this title must not exceed the aggregate reduction which would have been in effect on such day if— (1) a reduction of 3 percent ad valorem or a reduction of one-tenth of the total reduction, whichever is greater, had taken effect on the effective date of the first reduction proclaimed under section 2111(a)(2) of this title to carry out such agreement for such article, and (2) a reduction equal to the amount applicable under paragraph (1) had taken effect at 1-year intervals after the effective date of such first reduction. This subsection must not apply in any case where the total reduction in the rate of duty does not exceed 10 percent of the rate before the reduction. (b) Simplification of computation If the President determines that such action will simplify the computation of the amount of duty imposed for an article, he can exceed the limitation provided by section 2111(b) of this title or subsection (a) of this section by no more than whichever of the following is lesser: (1) the difference between the limitation and the next lower whole number, or (2) one-half of 1 percent ad valorem. (c) Ten-year period for beginment of reductions in rates of duty (1) No reduction in the rate of duty on any article under a trade agreement under section 2111 of this title must take effect more than 10 years after the effective date of the first reduction proclaimed to carry out such trade agreement for such article. (2) If any part of a reduction takes effect, then any time thereafter during which any part of the reduction is not in effect by reason of legislation of the United States or action under it, the effect of which is to maintain or increase the rate of duty on an article, is excluded in determining— (A) the 1-year intervals referred to in subsection (a)(2), and (B) the expiration of the 10-year period referred to in paragraph (1) of this subsection.