Rico,
I was putting my thoughts together when AMFBowler300 posted. He said exactly what I was thinking. If you grandfather the Jackals, you open the door for every company to cheat and get away with it. Yes, they have been out for 1.5 years....but unless you can pinpoint exactly when the balls began to be manufactured out of tolerance....so that you can separate legal from illegal by serial number (if that is even possible), you have to ban them all. Yes, it sucks for Motiv, it sucks for the bowlers and it sucks for our sport. But what else can you do? If you say you can use them for a few months to give Motiv time to replace. What stops a company from making a ball with a .08, .09, .10 differential, then just allowing people to throw for a season or 2-3 months while it is replaced? How many tournaments could won, money could be won, medals could be won, that would otherwise go to other bowlers if people were using legal equipment. Yes, this amount may not make a difference (although I suggested a scenario in another thread that I might be realistic), but if you don't stop it here, you allow for further transgressions that will make a difference.