I noticed this, too. Also, they often have us breed something that is only 4 or 5 hours of incubation time. The Lullabison was 12, and the Zeus Moose is 18, I believe. It makes my usual tactic of using a double boost when I hatch, then evolve the animal all the way to level 12 by using just a few gems to speed up 2 evolutions. 36 gems to evolve Zeus Moose 2x isn't that much, I guess, but I prefer to only spend 10 for a 5 hour animal.