Evidently you have worked for this company before successfully, so this does not sound like you don't 'get it' about what they generally want. If the requests for more detail are about the same items you already sent additional detail for, it is time to pick up the phone or email if they did not give you a phone number. It is completely appropriate to state, "I don't know what you are driving at. I thought I had given you the detail on these when I resubmitted. What am I still missing?"
Sometimes a second request for more info is sent because they didn't receive or haven't located your response to the first request. (No, I'm not going to say they didn't bother looking for your response.)