This is just a theory on my part, but maybe Ware lets up just a little bit when he's near the QB so that his body's more controlled and balanced?
It's true that he usually doesn't deliver a knock out blow, but on the other hand, you rarely see him get juked once the QB is in his sight. You sometimes see pass rushers who go full steam ahead whiffing on the sack as the QB slips left or right. You rarely see this happening to Ware.
Again, it's just a theory, but seeing as how he incorporates pilates and martial arts into his training (which preaches being balanced), maybe there's something to it?