In both cases, what you are doing is reducing the impact of the weightblock on the ball.  I have tried a number of balls drilled so that the pin is in my track or close to it.  It worked very well to tame the reaction of the balls on scorched lanes creating balls that arched to the pocket after getting through the heads reasonably well (if I kept the coverstocks sufficiently shined so that a track would not develop) and really didn't "snap".  On anything but scorched or severely broken down lanes, this drilling was not particularly useful for me (track around an inch from thumbhole, very little axis tilt or rotation at the time) as the milder balls I used it on lacked reasonable drive and wouldn't turn the corner -- so they either had to be thrown very straight or very far outside with a slight point.
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"I don't mind if you don't like my manners. I don't like them myself. They're pretty bad. I grieve over them on long winter evenings."