I think one of the other problems with mouthpiece sizing is most people go bigger on Bach mouthpieces. I personally cannot play on a bach 3C. My lead/rock/jazz piece is a stork 3d. Rim shape matters as much as the inner diameter of a mouthpiece.
Playing non-bach mouthpieces allowed me to find a rim that I could find comfy.
Most importantly, if you what you have works and is comfortable, don't switch :)