Ac, nstream, wep poll timeout

I have a sector were were are trying to push 200+mbps. We are running a metal box for the ap and sxt ac units for the clients using nv2. Testing at night I get 200+mbps but during the day only about 70mbps. Thinking this is interference (I’m sure I’m right… kinda crowded and using 80mhz isn’t easy on 5 seperate sectors). Decided to use nstream and it does seem to fix the speed issues and seems stable but if I enable encryption (wep40) all the clients just keep disconnecting with a poll timeout error. Turn off encryption and things work again.

Is there any reason why wep encryption doesn’t work with nstream? Anything I can do to use wep or wpa with nstream in a stable environment

Thanks in advance

On a side note:
Mikrotik staff… it would be a lot easier to diagnose interference and find free channels if we had a spectral scan ability on the AC units