Goods claimed to be the manufacture of a Developing Country, but not of any particular Developing Country, are the manufacture of a Developing Country, but not a particular Developing Country, if:
(a) the last process in their manufacture was performed in Papua New Guinea or a Forum Island Country; and
(b) they are not the manufacture of Papua New Guinea or a Forum Island Country under section 153L; and
(c) having regard to their qualifying area, their allowable factory cost is at least 50% of their total factory cost.