Clearly like any other wing characteristic the effects of aileron droop will be type dependant.
I can only speak for one type where under some circumstances the aircraft did not meet the takeoff performance guarantees in respect of distance. We added a bit of aileron droop and gobbled the spec.
In my view it is likely that when aileron droop is used people are only interested in the lift benefits and so ignore any drag issues as the time the droop is down is so short any drag delta does not matter.
It probably makes sense to think of droop as just increasing the amount of wing that is flapped.