Questioning VGchartz Numbers?

[Grey Acumen]

I'll be honest, I find VGChartz hardware sales to be reliable all around, but unless it's a really significant game, I don't expect much out of VGChartz accuracy. A lot of the games get added by regular forum members, but I'm not sure how it's handled for the actual tracking. There are some games that don't even have numbers, especially with less known or older games.
I'm not sure why the numbers would come out higher though, I'd have to know the specific methods for tracking. It's possible that when they gets teh software sales numbers from companies, some didn't even have the game listed, and so they guessed at the numbers in those stores being similar to numbers in stores that did list the game, but in reality, those stores didn't sell many, or perhaps didn't even carry it at all.