I was at the range one day shooting my Shield 9mm and a friend asked me if I'd like to try his FNP 45. Of course, I said yes. I have to admit that I flinched just a hair in anticipation of the 45 kick. I pulled the shot about an inch to the right. But, it was all in the anticipation, because if you've ever shot an FNP 45, you know it shoots like butter. (I think my 22/45 has more recoil!) I put the next 4 shots through a single hole!
Try the suggested grip change, and try more hearing protection. Practice makes perfect! You'll get 'er.