iv ebeen working at a small pro shop for a year now and i have always noticed that your high end balls the mb is amost always marked. my question is why dont they take the time and mark all balls that way it would make it a heck of a lot easier to layout balls for bowlers who want a specific layout. i know that they have machines and so on to find the mass bias but in a small shop like ours we usually dont do enough business to invest in one.

For what it is worth, the "theoretical" mass bias on a symetric ball is a point 6 3/4" from the pin on a line drawn from the pin through the cg.  But on symetric balls the mass bias is so small that it does not come into play before drilling the ball.