Generally speaking, the headquarters is but a small fraction of the total workforce so even if there was an actual return to the USA I doubt we'd be talking a significant number of people. Apple makes most of there products outside the USA, mostly in China, so of the roughly one million people that work in some capacity for Apple the domestic workforce is a tiny fraction of the world total. And, as many companies that make products in the semiconductor industry are actually fabless the actual workforce employed in the USA is mostly headquarters, design and programming.
Just as with accounting it's not hard to journal things around to make whatever picture you want. The motion picture industry has played the game of paying big stars a percentage of the net for a film, but because accountants can move things around even hugely successful films can be made to appear as though they just broke even. It's all a game!
Brian