APM license query

Hello All,

I have a query on APM licensing,

1 CCU = 1 Concurrent user ??? kindly confirm

secondaly, for i5800 min CCU is 500 and Max is 20000 CCU, Please let me know the concurrent users supported by i5800 by default.

If im buying i5800 with APM module license , does this include base 500 CCU or do i need to buy additional base 500CCU license along with APM module license.

Appreciate your comments.