Oh, so according to Serebii, if you have the EXP share on, all of your pokemon gain 50% EXP, not just 1/N for a team of N pokemon... I kind of wish I didn't turn it off. Sounds like you could quickly get a big team that's all overlevelled using that. I mean I ended up with a team of six level ~60-62 pokemon after beating the Champion, with no (intentional) grinding, so if I knew EXP share worked like that they'd have likely ended up closer to level 70.