This has nothing to do with the value threshold. US customs had to know the difference between personal packages and commercial packages before the change.

You asked me what distinguishes a commercial package from a personal gift.

> US customs had to know the difference between personal packages and commercial packages before the change.

Presumably for things like import restrictions (I could imagine somebody sending homemade cookies is treated differently than a large-scale food importer), but not for a decision on whether to charge or not levy duties though, right?