I AM BAFFLED. I must be stupid.... I understand that for on iTunes account, I can use it on, I think, 5 "computers" and 10 "devices." Right now I have two computers, two iPhones and one iPad 'authorized." Thats, it. It will not allow me to add any more computers (i.e. Macs.) Would/can somebody please tell me how this actually works? How many computers (ie macs) and how many ios devices can I use on one iTunes account? Many thanks!