Squeezing bowling ball

Question
I am having an issue with my bowling equipment.  I seem to be squeezing the bowling ball too much.  If I really slow down my approach, I do not squeeze the bowling ball nearly as much and get much better roll on it but then I am only throwing the ball around 10 mph (which is way too slow).  My track is about 1 inch away from the fingers and thumb when I slow down.  However, when I speed up or try to throw the ball faster, my track goes way down and I go over the top of the ball due to a late release (which I believe comes from squeezing the ball so much and the thumb coming out late).  I have had custom thumb molds made and about two years ago the ball seemed to fit perfectly and I really didn't have to think about my release at all and my speed was between 12 to 14 mph.  I could hold the ball down at my side comfortably and really didn't have to put pressure on it to hold it.  Now when I hold the ball at my side, I do have to put some pressure on it to hold it there.  The size of the thumb hole seems fine to me, but I am wondering if maybe a pitch change could help because if I add tape I am not getting out of it clean either.  I am thinking that maybe using the same custom insert with more forward pitch would make the ball feel more comfortable without the squeezing.  Unfortunately I don't know my pitches for sure but I believe my thumb pitch is at zero.  I know my span is correct and like I said my thumb seems to feel like the right size.  I am a right handed bowler (6 feet tall 170 lbs) and would love to get better but I believe my equipment fit is preventing me from getting there.  Any help with this would be much appreciated.  Thank you.

Answer
Ron,
Not much information but, what you did mention sounds like you're squeezing. If you can provide all the details of your grip and some details of your hand I can evaluate if anything jumps out as a problem.

What kind of changes have been made from the two year old stuff and your current equipment?

As you speed up, clearly you are working harder to hold onto the ball. Pitches and span comprise the largest segment of a proper fit. Just changing thumb pitch might help, but without more detail, it's just guessing.

Have you relayed the concerns to your fitter/driller? It's hard to bring bad news to someone trying to help, but your driller needs to know things are not working out. And I'm sure they'd welcome an opportunity to adjust the work. They want you to be happy and successful. Some just hope, and assume.

In my experience, many of my peers believe they are competent, and many are, but without feedback, especially negative feedback they don't know if things are working, they just assume. The last thing a store operator wants is a customer dissatisfied with equipment that doesn't feel right or doesn't perform well, which might lead to a bowler leaving the sport. Millions have in the last 15 years. So follow up is not only prudent but in my mind crucial.

I try to follow up with all my ball customers, because of exactly this situation. I guarantee my work and it's not just a marketing promise, it's my philosophy. Perfect is an acceptable level of performance.

Sometimes perfect takes adjustment. Wanting something to be right and having the courage to follow up and make sure it is, is the difference between many drillers and good business people. Unfortunately, people don't know what it takes to be good at this. And many, obviously, learn by doing and charge bowlers like yourself for the opportunity.

Thanks for your questions. Can you get me the information?