To clarify, you can only have one figure on at a time; however, the Tama-go keeps count of how many figures you have put on for ALL TIME.
So, let's say that you get your Tama-go, the lite figure, and one extra figure. After you put both on, the count will be at two. Then, two months later you get another figure and attach it; the count will go up to three. Does that make sense?