_scr00bius_

That's not how corporate commercial agreements work.. apple would better immediately bogged down in multiple, endless negotiations and trial periods. As a developer, I don't think you should want apple involved in your processor choice at all

Most payment processors do not calculate taxes on purchases, especially not online. The merchant of record does of course, and in this case apple would be both the merchant of record and processor so it's moot. But if you wanted to make this law, aiming at the processors wouldn't get you very far