is it the same for a 14 lb and a 15?

Unless the balls have different rg and differential ratings for the different weights, there should be no differences.

what about for a 2 hander? The pin on my two different gross weights, , both top weight 2.8 , is located in different positions on the ball?

 What two balls are we talking about?

How many holes does your ball have...
2 finger
3 finger
2 finger one weight hole

The TW/CG should be within your grip center... So if you have two balls the same/ish and only a pancake block the question is a big elephant.

When did you get holes in your ball?

Before you said you didn't have holes and was the worlds only hole-less bowler.

Does anyone have more information on why do two balls of different weight have different pin to CG measurements?

ok.

 Pin to cg measurements vary due to manufacturing differences. On plastic/polyester balls, the cg is usually the "heavy" spot on the surface of the ball, and the "pin" is usually just a mold mark where the inner core was held during the pouring process, and might end up nearly anywhere on the ball, depending on the manufacturer.

 Pin to cg really only becomes a factor in balls designed with more dynamic cores than a pancake cored plastic/polyester ball.

Where's my basement troll ignore button,dam*t  !!