He means as in different kinds. Like if you have a GBA and a GBC, then you'd have two types of handhelds. But if you had two GBA's, then that only counts as one type of handheld.
Edit: What the hell! I just looked on the first page. I totally did not do that. It certainly wasn't like that when I first posted it, and I haven't edited it.
Edit: And that fixes it. I still don't understand, though...