if you see the popup, the editor notice the actual stats value are different to the calculated value (original plus experience point).
However i don't know (the editor don't know too) the right value.... you may try to save with my editor without change (you open savegame, see popup and save).
I did it! xD I had to low some stats. And, can I change position? Being a Striker kinda sucks because I cant see the ball often (yeah, my team sucks lol). I want to change it to an attacking midfielder