So I just started playing with Mexes...never paid much attention to him before. He has 6 goals in his first 5 games for me, so I had to find out if he was this crazy for everyone. Apparently so.
Thing is, its not just the headers/corners, which he is great at. But in his skills he has "gets into opposition area often" and "gets forward whenever possible", so he just jumps into the attack if you don't restrict him too much. 2 of his 6 goals for me were just normal shots in the box.
Anyway, amazing player!