Are you sure you have 500AP license?
By default you get 250 APs license for nms-adv-25.
What version do you use?
If you have more APs you will not see stats for those APs, you will not be able to place those to the maps...
Not sure if there are more limitations or more escalations of restrictions. Anyway it can be version specific, so with version 9 it may be different.