I was wondering to the bowling Guru's on here about this question : obviously the balls of at least 15 years has a drastic effect on ball reaction/motion, but with some of my older balls from the 90's that were designed for mostly durability, that when I have changes the surface on them, they give such UNUSUAL BALL MOTIONS AND REACTIONS: And I wonder why that is.

To me it acts like nib balls of today that once you adjust the surface, it's gone, only difference is that again it appeared that balls back then had very similar finishes,  not focused on a particular finish,

To make a long story short, I have just picked up a few oldies,  and they react good, but are obviously worn out (the coverstocks)  and was open to changing the surface, but afraid to lose the initial reaction, what did I do?  And why is this?  Thanks for any feedback.

It is not just the lane - it is the ball return also.  All the belts, rollers and fabrics that collect, move, accelerate and then slow the ball do the sanding/polishing.  Otherwise the change would only be in the track of the ball.  The measurements show changes everywhere.  I suspect that the ball return is the major actor in changing the surface of the ball.

Thanks avabob, this is exactly what I thought it was the way you explained it, much appreciated.