Just noticed the differential numbers on the Xxcel, and noticed the 15 lb. weight is .063 and the 14 lb. weight is a whopping .075. Is this ball grandfathered in before the new change in USBC differential specs, or because it's legal in a 16 lb. weight does that make it ok for all weights? I'm sure the ball is legal, as that would be a huge mistake if it wasn't, but just wondering why it's legal, if it's because of the grandfathering rule, or because of the 16 lb. being legal. Thanks everyone.