Customs examiners assess invoice values, including non-usable charges, which are typically excluded from regulations. Fees like merchandise processing and harbor maintenance are calculated based on specific values. Rounding errors can create significant margin errors affecting customs assessments. Knowledge of CBP forms, such as Form 7551 and 7553, is essential for drawback claims. Customs may require extra documentation if discrepancies occur in the drawback entry.

#Code of Federal Regulations (CFR) Title 19
#Part 190