I don't know which EB1 you are. Our's is EB1 extradinary ability. Got RFE too.
We got similar question like yours. We just ignore it. Since salary is not the only evidence for EB1. Focus on other evidence you could give, like REcommendation letters.
For our understanding, you could not judge a person's ability by salary. But you don't want to argue with INS. So we just ignored it.
Our case got approved after 3 weeks RFE was sent to CIS.