Withdrawing more than the RMD from an IRA BDA

We have each inherited an IRA, and set up appropriate IRA BDA accounts. For personal reasons, we are withdrawing well in excess of our RMDs. TT is asking whether all or part of this distribution was an RMD, and if only part of it, then how much was the RMD. I can understand if I'm withdrawing *less* than my RMD, because explanations and penalties would then ensue. Since I am withdrawing more, how accurate does this answer need to be? 

Mine is actually simple to figure out, spouse's not so much. Short version, the funds are in two separate institutions, one of which was disputing how much of it we were entitled to. We succeeded in withdrawing a plausible amount, based on our calculations of the estimated total, but how should we answer the same question? Again, we are withdrawing more than the RMD, so how accurate does the answer need to be?