You must be a pretty high tracker.  PSA on PAP will generally put the pin in your track and virtually eliminate any dynamics the core has.

PSA stands for Preferred Spin Axis, and is one of the stable axes of rotation that the core has.  Putting it on your PAP means the core is already pretty stable.

It would make the ball stronger, but moving the pin closer to your PAP and putting the PSA past it might help eliminate the weird tracking problems.  Strong asymmetric cores like the recently departed Zone core do goofy things when you put the MB in odd places.  Like in your track or on your PAP.

SH

not that static weights matter but i am thinking if the CG is inline with the ball and example the cg is 3 oz and 3 inches long, you would have your cg above your midline. producing more finger weight. So moving the balance hole farther down your VAL towards your thumb quadrant wouldn't be possible.

You say under and slightly next to your middle fingers? that sounds like it is too close to your track. like shelly said redrill the ball with the pin slightly closer to your PAP. It's too far right. Your PSA could end up on your VAL or past it up to 2 inches without any ill effects really.

Simple answer your Pin is too close to your track and causing the ball's core to flare backwards.

In any case, Pin position is more important than MB position so the PSA/MB being on your pap has nothing to do with the ball flaring over your thumb.
--------------------
Timothy @Juniors Pro-Shops
LaSalle, Quebec
Located inside Pont Mercier Lanes.
Edmonton, Alberta.
Located inside Ed's Rec Room.(WEST ED MALL)

Roto-Grip Star Proshops
Etonic Stabilites Dress wearer.

Montreal, Quebec.