Another thought:
When did you determine that you were pulling the ball 2-3 boards inside your target? Right after your release when you watched the ball go over your target area or only after watching the video? I think most bowlers miss their intended target inside by 1-2 boards and it only becomes apparent when someone else is watching or they view themselves on videotape. But, at the time, it should look like you hit your target.
So, if you know you are missing your target at the time of your delivery, then you have a problem. If it only became apparent after viewing the tape, that might be normal.