I know there has to be an explanation as to why I do this.  The past couple of weeks, I have gone from carrying good to not being able to carry to carrying.  So, I re-tooled my game, and found that I was jumping the ball, with limited hand rotation.  Anyway the problem that I have is at one of the houses in which I bowl, I still consistently leave ringing tens.  Yesterday, I noticed something, every higher bowler average in the house was quite vertical at the foul line.  After my first game of leaving usual 10 pins, I decided to pop up at the line.  And it worked.  I didn't switch ball, speed, move, or adjust hand position.  Why is this? Is it changing the way the ball is entering the pocket?  Explanations?