I agree. It is about the same amount of material as before. So I don't see why they would have to use double-sided discs. I really don't think they need four sides. Season 1: 8 eps + 4 specials + 2 shorts= about 300 mins Season 2: 13 eps + 1 special + 5 shorts= about 350 mins
They had different opening and closing credits, but they were changed once Nick started running them in regular rotation. I'm guessing they didn't want to confuse the kiddies.