I just recieved a Tennis Tutor Plus Player today and read the owners manual. It says that you have to break in the machine by using used balls. It says that if you use new balls, the ink will come off and make the spinning wheels slippery, leading to inconsistent ball throws. I was wondering if this is necessary because I only have around 40 used balls, but just bought 140 new balls. I've already shot about 250 used balls out of it. So if anyone has used new balls on their machine, or knows that it's essential to use used balls, please tell me. THANK YOU SOOOO MUCH!!