Currently I'm on the lvl72 in OG.
When I tried to play NG+ I realized that I'm on the lvl 63 in the game.
To fix this restarted NG+ to rebirth1 and switched back to OG in order to kill GKing. Now in OG the experience of the most of my items (masterd them all) have been cut in half?!?! Wht the hell is going on?!?!
To the contrary, all my money and character statistics have remained untouched.