If it really is that way, well ok. But weird that you can't read about that anywhere in the game and that it is a hidden mechanic for some mysterie, which I do not see any logic behing that at all, but ok.

On paper it just looked like it was a feature of +2 and thats why at Y+2 nothing is said about that, which would also be very very logical and correct, but if its a hidden feature, well, fine. Got you. Have to stop using logic in this game then.