Hi HB,
Yes, having inserts too large may be causing you to squeeze the ball, which then in turn can possibly make you rotate your hand faster in your swing then it should be turning. If you weren't topping the ball before this and the grips were fitted properly, I'd definitely recommend that you change these to the correct size, it should help.
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Rick Leong
Ten Pins Pro Shop
Track Pro Shop Staff
Vise Grip Staff