I can't answer your question without knowing more details. You say there are "loans" on 3 units roughly only $25k. Is that 3 loans? Thus 3 x $25k. If so, your total loan anoint is $75k and that would be the "lesser of 3".
You need (as a minimum) the lesser of:
1. Loan(s) balance. Use the combined loan amount;
2. Insurable value. You won't get a payback on a loss of RCV because this isn't a single unit. It's 16 units.
3. Max available - $250k for each dwelling unit.
You might benefit by reading the article at our website entitled "Flood Insurance Insurable Value". You can find it in the "Free Downloads" section at our website: https://www.bankerscompliance.com/resources/
That will also explain why you shouldn't get RCV