Where does it say that, Redmonkey? Because the Star Wars Insider, the official Star Wars magazine, says that as soon as the Clone Wars ended, the Emporer started to recruit men to act as clone hosts for additional clone armies, meaning that the clone soldiers would not all be from the same man anymore, but they would still be clones. It is possible I guess that eventually all of the cloning tubes were destroyed, but certainly not in the early years of the empire.

yes, but only for higher positions like Grand-Moff Tarkin