Exactly, you don't know whats under the top coat of paint untill you scrape it off.
The plains anery is a dicey one, to me, it shows classic characteristics of anery, axanthic, and melanistic, and the same could be said about the eastern melanistic(which also has a subtractive effect on pattern), which all 3 labels(anery,axanthic,melanistic) get kinda muddy. For me, one thing that really kind of helps demonstrate whats going on or gives us some evidence as to what is going on, is what it does in combination with albinos, and the end subtractive result seen in the different snows.