Customs classification: populating a PCB does not automatically qualify imports for component rate of duty; factual assessment required. The Circular removes an illustrative sentence that suggested populating a PCB automatically amounted to 'working on' imported components and thus entitled importers to the component rate of duty. It states that the example was not intended to create an automatic rule; rather, whether components must be further worked upon is a question of fact for the assessing officer to decide based on the totality of imports, and accordingly the last sentence of paragraph 6 of the earlier Circular is deleted.