I don't know why it's been such a big deal lately for Paul to want to switch it from Lennon/McCartney to McCartney/Lennon on some songs, ie Yesterday.
Everybody and their mom knows who wrote Yesterday, so it's not as if he's not getting the credit he deserves for writing it.
I know he switched around the Beatles tracks to McCartney/Lennon on the Wings Over America album back in the 70s. John was obviously still alive then, but I've never seen anything said by John himself that he was p*ssed about what Paul did.
Paul has said that he was wrong to want to switch the authorship around a few years ago, but I don't know....