This calculation is a bit confusing. Are you limited to only buying 13 bundles? Could you not buy all of the songs in bundles? If so, that's pretty lame by itself.

As is, it looks like you'd have to spend something like $75 on the iOS game to get the same thing as the $30 3DS game (not including any extra characters the 3DS version comes with). So yeah, that's a bit ridiculous.