We have the exact same problem with Dyn, and it's pretty much just a way for them to make more money off you. Leaves a sour taste in your mouth, and I doubt most people even notice the extra req/s they're being billed for.
If there was an alternative, we'd switch. DNSMadeEasy does not charge for those AAAA requests, but it's not quite at the same level UI/functionality wise.