It probably is, but what is probably happening in your situation is there might be something in your C-file that your IMO's didn't address that may be important to the claim, and the RVSR is trying to get a medical determination as to that particular issue. Or it's possible that your IMO's doesn't contain any rational for the doctors opion, such as references to sound, peered reviewed material, and the VA is trying to substantiate those IMO's from another source. However, it's hard to say because I really don't know your situation and the evidence and IMO's you have already sent to VA.
I have sound medical opinions with supporting medical treatise. They just give more credibility to the unfavorable opinions who have not submitted any medical treatise. Furthermore the C&P esaminations have been a joke. The examiner doesn't even have my records nor do they do a complete exam according to the Clinician Guide.