I agree with you that it would have been irresponsible of the FDIC to have put such a low value on a banks housing assets, especially during a time when the Federal Reserve was requesting 700 Billon in funds to help finance the securitization of banks that had balance sheets which were heavily skewed by the depressed housing values at the time.
I think the FDIC is probably working on the reconciliation of which assets JPM wants to now purchase, and perhaps which of the ones they don't want could be sold to someone else.