Where any order under paragraph 1 or 5 above directs that, for the purpose of any duty or of any drawback, goods are to be treated as not containing or as consisting wholly of a particular article, the goods shall be so treated also for the purpose of determining whether any other duty is chargeable or any other drawback may be allowed, as the case may be; but any duty or drawback which is charged or allowed shall, notwithstanding the direction, be calculated by reference to the actual quantity and value of the goods and, except for the duty or drawback to which the direction relates, by reference to their actual composition.