I wouldn't be surprised if it was something to do with energy. I have two level 50 games and got the higher requirement on the game where I have a collectioon of alicorns unicorns and a weekly horse and unicorn. I've also completed the storyline apart from the mermaids and the leveling up stuff on this game. On the other game I have a fair bit of story to go and only one wizard school one Ali and a weekly unicorn. And this one triggered the lower level requirements. So if not energy based it could be something to do with completed goals, but this seems unlikely.