NVC usually review the re-submitted documents after 12-13 days. Waiting time restarts again after every new submission typically. This is based on my personal experience during one and half month dealing with nvc processing. Sometimes RFI messages are not very obvious. Sometimes your accepted document become invalid the very next day after it is ACCEPTED and you have to resubmit it. It is better try to submit documents as per I-864 instructions and CIVIL document guidelines based on your circumstances initially so that document review cycles can be reduced. That is what most of the folks on this forum are doing