This document conforms the Customs Regulations to existing statutory provisions and judicial precedent regarding the assessment of interest due to underpayments or overpayments to Customs of duties, taxes and fees pertaining to imported merchandise, including interest thereon. The majority of the conforming changes reflect the terms of section 505 of the Tariff Act of 1930 (19 U.S.C. 1505), as amended by section 642(a) within the Customs Modernization provisions of the North American Free Trade Agreement Implementation Act. Under that statute, interest accrues initially from the date the duties, taxes, fees and interest are deposited with Customs in the case of overpayments, or are required to be deposited with Customs in the case of underpayments, but in either case not beyond the date of liquidation or reliquidation of the applicable entry or reconciliation. Also under the statute and applicable judicial precedent, all bills issued by Customs for underpayments of duties, taxes, fees and interest are due within 15 or 30 days of issuance. In addition, the document conforms the Customs Regulations to other changes to 19 U.S.C. 1505 and to section 321 of the Tariff Act of 1930 (19 U.S.C. 1321) regarding interest that were made by sections 2(a) and 3(a)(12) of the Miscellaneous Trade and Technical Corrections Act of 1996.