Project-GC understates my finds by 1 geocache on the basis that I have 1 duplicate log. My duplicate log was for GCHDVW, Split Decision, which was a multi that had two distinct geocaches. You went to the initial coordinates and there were two sets of coordinates, one for an ammo box in the woods and one for a micro in the woods and the idea of the cache was that, at least initially, you didn't know which you were looking for. Since there were two separate caches, the owner allowed people to log it twice. Obviously you can't do that today.
I know that there are exception lists for other statistical categories (like furthest from home) to prevent odd old caches from skewing the statistical results. Is it possible to have an exception list for this as well?