Most likely you are still squeezing the ball. Try to hold the ball with no grip pressure at all from start to finish. When you squeeze the ball you kill the revs. The ball should leave your thumb right at the bottom of the swing, not out past the toe of your slide foot. Keep in mind that before, when you had no backswing most likely part of your swing took place out in front of you instead of behind you. The part of the swing that took place out in front of you caused you to hit UP on the ball giving you more revs. You may have had less ball speed as well…depending on how much you muscled the ball.
Today’s modern releases that are performed without squeezing with a higher backswing, can produce a higher rev rate than the older style release of hitting up (lifting) on the ball. The increase in revs comes from having your hand in the right place at the right time and using the momentum of the armswing to go through the ball. This takes time and effort to learn. It’s pretty easy once you learn it but it is not easy to learn.
Don’t be surprised if you have to go with even more forward pitch in the thumb in order to stop squeeze the ball. I currently have ½ forward pitch in the thumb and I am pretty sure I can go a little more.
I have a guy here now that came from Norway for lessons and wanted us to drill up a couple balls for him as well. He brought a drill sheet with him that called for 5/8 reverse in the thumb. His hand was pretty close to mine so I ask him to go out and throw my ball a few times before we drilled the new one. I instructed him not to squeeze the ball at all and give it a try. He threw the ball great and was very surprised when I told him it had ½ inch forward in the thumb. Now I can give him lessons knowing that he will not be squeezing the ball.
Good luck and bowl great!
Ron Clifton