Maximum busy value is in percentage so it is 100%
if busy is 100% then 1) if it is continously seen on 100% then either hardware is faulty or environment is super NOISY for AP to operate
2) User won't be able to connect as they will not see beacons as AP won't be able to trasmit them due to continous interference.
if i would be in your place then i would take the AP to another location to test: this will confirm 2 things
AP is good or bad.
confirmation on existence on heavy interferer..
