Hey Rock,
You are correct, pin to pap is the important thing but when we start to push our pap limits or cross over centerline, it helps control or delay reactions.
I'll try to explain it like this, leverage is at 3 3/8, it is the strongest position to place a weight block to an individual's pap so the further we extend it (4-5 pin), the longer it will take the weight block to reach it's psa (preferred spin axis). If we placed the pin under 3 3/8 (1-2 pin), that block would fall very quickly and the ball motion is very early to possibly roll-out.
Once we cross the centerline (true numbers are 6 3/4), we used to call it cheating the pin (different drillers may refer to it differently), it now places the controlling weight on the other side of the ball as it's rolling down the lane. Ever drill a pin in track? At about 10:00 from cg (left of mid finger), this causes the ball to go extremely long and pretty straight because the controlling weight is now on the other side of the ball as it's rolling down the lane. Another way to look at it is because it is so far from pap, it takes forever to reach its psa. In all honesty, I don't know if it ever does, I guess it can if it were given enough time.
Example: Brian gave a me a full roller layout for one of my spinner customers. By placing the pin at 7:30, it actually pulled his track back up towards his grip because the weight block is sitting in the thumb negative quadrant which is how we drill statics to help a bowler roll early. With the weight block there, it wants to pull the ball left to right vs right to left which is the reaction or look we normally get when the weights are centered or on the positive side of the ball. Pm me bud if you want more details or I'll write forever...
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Rick Leong - Ten Pins Pro Shop
Track Intl. - Amateur/Pro Shop Staff
Vise Inserts Staff
Trackbowling.com