(1) Unless the contrary intention appears, if, in a rate column in Schedule 3, 4, 4A, 5, 6, 6A, 7, 8, 8B, 10, 10A, 11, 12, 14 or 15, reference is made to a percentage in relation to goods or in relation to a part, component or ingredient of goods:
(a) the reference is to that percentage of the value of the goods, or of that part, component or ingredient of the goods, as the case may be; and
(b) the percentage is a rate of duty.
(2) The value of a part, component or ingredient of any goods
for the purposes of this Act is, unless the contrary intention appears, such
proportion of the value of the goods as the Comptroller - General of Customs
determines.