Assuming you've upgraded to A6 from A5, what you are proposing is infact NOT legal. You will loose your license when you sell your A5, because it's not the version you're transfering to someone else, but your license. So, infact you're not allowed to sell your A5, without selling your A6 version too,it's all about the single license you've got. Why would one need to pay for blank cds by the way? You've got to send the original cds, not copies ..

Cheers