Customs duty cap on wheat gluten limits payable duty to a fixed effective ad valorem rate under a statutory exemption. Exempts imports of wheat gluten under heading No. 11.09 from customs duty to the extent that duty exceeds the amount calculated at an effective rate of 15% ad valorem, fixing payable customs on those imports at that effective rate; issued under section 25(1) of the Customs Act, 1962 on public interest grounds.