Exactly the same happened to me, pretty much you described me lol and let me share with you what I decided.
I went to 3 fingers, why? consistency, with 2 fingers my highest game in 1 year that I played like that was 257, but as I was capable of a 250, 230 I could throw 120 because the timing you give the ball on you backswing and some other stuff isnt the same as with 3 fingers. I've been bowling with 3 fingers for the last 2 and a half months and I already bowled 240, 231 as my 2 highest games and there is plenty of room to improve! I feel alot more consistency in my shots and my physical game is way better, so I'll tell you what my coach said (former wichita state champion) either you go 2 hands or 3 fingers.
2 hands more power: more trouble with drier lanes or lofting plus you need a tremendous physical game
3 fingers: more consistency and less effort to your arm. I was using 14 with 2 fingers and now with 3 I barelly feel the ball's weight.
Hope this helps!