I got an answer back from them (two actually). I thought their explanation didn't make sense and ended up with a confession that it is inconsistent.
The stats show ALL the games, including those from the 3 free bonus packs. If you look at Quick Play and Challenge, they ignore the bonus games. That's why you get 60 reported in some cases and 80 in another.
I think they're a bit embarrassed to have it pointed out. What are they gonna think when they see it posted publicly? (evil smilie here)