Where:
(a) any warehoused goods are examined by an officer or by the owner of the goods with the approval of an officer; and
(b) the examination shows that there has been a decrease in the volume or weight of the goods since they were first entered;
the volume or weight of the goods shall, for the purposes of this Act or any other law of the Commonwealth, be taken to be:
(c) except where paragraph (d) applies--the volume or weight found on that examination; or
(d) where, in the opinion of a Collector, that decrease is excessive--the volume or weight shown in the original entry reduced to an extent that the Collector considers appropriate;
and duty in respect of the goods is payable accordingly.