When a ball is plugged the actual CG is moved - correct. However, the "marked" CG does not move. Given the preference today for hi-flare layouts and exotic drillings that require balance holes, the marked CG is often more than 1" from the grip center. With the vast majority of balls the bowler will need to have the entire ball plugged and re-drilled - not just the balance hole. Worse, when this work is done, the plugs will likely be in the bowler's track. You can argue good or bad - but the fact remains if these rulings come to pass a whole lot of bowlers will be buying new balls in '08.
An example of how stupid this can get - I have a Classic Zone with a fairly tame layout - pin over bridge (6" from PAP and the mass bias below the thumbhole (right edge). This ball had a marked CG around 1-1/4 to the right of the Pin to Mass bias line. Because of this, it needed a small balance hole. To make this ball legal in '08, I would need to plug and redrill, and the mass bias would end up on the left side of the thumbhole near the track - A definite NO-NO with this ball and core. So - it turns into junk. (Unless I find a lefty who wants it).