Butcher and AA modifiers

So I was looking at butcher and saw that it works with single target spells. So just want to know how does this interact with AA modifiers(i.e. Jax' Empower, Nasus' siphoning strike, etc. )? Will the mastery proc once from just the AA or will it proc twice from the effects of both the AA and the AA modifier?

Edit: Was just tested with Nasus, it only seems to proc once.