I have to say something that gets over looked. Most bowlers who don't get the ball down the lane or don't get a good backend reaction comes from 2 things. Rushing the first 2 or 3 steps early on and beginning at the release into the follow through they come straight up rather than reaching out. What also happens is bowlers slow their feet down early on but don't slow their push away down. By the time they drop the ball down where their arm is vertical their timing gets way off by the 2nd or third step. Remember if you slow your feet down, slow your push away and drop away down too and reach out a little bit more. This will help you way more than changing wrist positions.