Hi Shelley,

Sorry it took so long to respond, but I completely missed your question.  From what we have seen, most pro shops simply want to see the shape of the core, and know how the core is laying inside the ball.  By marking the AMB cap with the locator pin, they can look at the image of the core and determine exactly how the core is positioned and drill the ball accordingly.  

The VMB (virtual mass bias) is simply the spot on the ball directly opposite the AMB Cap.  This spot is typically where a heavy cap would be located in order to create the same dynamic effect.  It's a little hard to explain, but essentially, you get the same dynamic effect by removing weight from one side as you do by adding weight to the other.  Obviously there are other details that have to be considered such as core, cap, and wrap densities in order to get the correct topweights, pin positions and total weights, but that is another topic.

Another small factor is that the ball already has three logos, the CG location with the Serial Number, a flip cap pin and a locator pin.  The ball was already getting a little busy and confusing, and our understanding is that most pro shops would just prefer to have the locator pin showing the cap location.

Hope this helps, if not I can try to go into a little more detail,

Jason Wonders
Visionary Bowling Products