I think it is ANACS policy to grade that way. They give you a grade for the actual wear, or lack thereof, on the design but nore any other problems like cleaning etc.
That is one of the things that people see as a reason to go with ANACS. They note the problem on the slab rather than just sending the coin back to you ungraded like PCGS and NGC do. Although I"ve heard that PCGS is supposed to stop doing that.