MBs are not lenders, it's not their money, and they don't make loan decisions; and neither do the loan officers at a bank make loan decisions. That's the operative distinction in both FIRREA and D-F rules. Keep the loan salesmen out of the appraisal engagement loop.
Lenders can and do comply with FIRREA and D-F who employ their own in-house appraisal staffs which do not answer to anyone in the loan production side of the business. Chief Appraisers at these lenders are commonly a VP slot which (in theory) has parity with the VP of loan production. As in, peers with loan production, not subordinates to loan production.
That's not to say the lenders always adhere to these rules, but those are the rules from the regulatory side.