Hypothetically, if a character wanted to create a version of Mad Monkeys where the swarm was able to do 1d8 energy damage on top of their normal damage, does that sound like it should be one level higher than before to you?
I would say the extra spell level should warrant more of an improvement than 1d8. Perhaps make the distraction DC equal to spell DC in addition to the elemental damage? Perhaps have it give two swarms. Something though.