RGR - yep, that can get in your head.
82Boat is absolutely right - make sure you either have your fitting specs or that your Pro Shop
has them and is always the same.
I recently went in because my White Dot felt different - but he measured it and it was drilled the same - except that the thumb hole was way flared. He removed it and put a new one in with way less flare and, bingo, feels the same as the others. Makes it much easier to throw (have only missed 1 or 2 10-pins since.
Practice a short memory! I know that sounds strange, but focus on THIS ball.
My left knee is shot. I wear a heavy duty brace and get cortisone until it's time for a new one. Now and again, I will put down my slide foot on the outside of the sole and it will stick - and I have to focus on forgetting about it next time. Focus on sliding FLAT. Slide FLAT. Slide FLAT. That goes into my little mantra as I deliver.
I also have a thumb plug in my box - just a plug that's drilled a touch too small. When my thumb starts swelling or anything, I will jam my thumb in there and play with it a bit. . . helps keep my thumb the right size.