Was your home insured through National Flood Insurance Program (NFIP)?
Is the home your primary residence? i.e. Did you live there - not a second home.
If the two above is yes, and your policy provides Replacment Cost Coverage,
and you are planning to replace it, then the ACV amount does not matter.
Just replace it, and then submit for the Replacment Cost Claim.
If your policy does not provide Replacment Cost coverage, and the Actual Cash Value
claim will conclude the claim forever, and you dispute the claim amount,
then read the "Appraisal" provision portion of the policy.
I Post Large, it is easy on old eyes!!