Division 2 The dutiable weight, in the case of goods chargeable by weight, and the weights by reference to which the scope of certain headings or subheadings is defined, shall be taken to be:

in the case of a reference to ‘gross weight’, the aggregate weight of the goods and of all the packing materials and packing containers;

in the case of a reference to ‘net weight’ or simply to ‘weight’ without qualification, the weight of the goods themselves without packing materials and packing containers of any kind.