I do not know from personal experience but if an AA and a CRNA work for the same group with the same rules of employment and one does nothing that the other does not do, then I would expect they get paid the same amount, with a small variation for experience and length of employment.
However, if the CRNAs cover OB, which they can do independently, then I would expect the CRNAs to get paid more as they are doing more and taking greater risk on their shoulders.
What we need is comment from a CRNA or AA who work in a mixed employment situation.