In reply to Thomas.

Yes for some rooms we noticed that we were hitting the limit of 200 clients per AP.

It's unclear if adding AP's will help this situation: given that our connection to the U building is 100Mbit/sec, adding AP's might send more traffic across this overloaded link.

This would make the problem worse rather then better. Adding AP's after upgrading the link to U would be labour intensive, but would fix the problems.