I found in the Iowa Code 655 the below statement....it does not specify that a Vice President or above are the required signors. I would contact a real estate attorney to check for any special requirements they know of in the Iowa code or what documentation is needed to back up the signors authority.
655.1 WRITTEN INSTRUMENT ACKNOWLEDGING
SATISFACTION.
When the amount due on a mortgage is paid off, the mortgagee, the
mortgagee's personal representative or assignee, or those legally
acting for the mortgagee, and in case of payment of a school fund
mortgage the county auditor, must acknowledge satisfaction thereof by
execution of an instrument in writing, referring to the mortgage, and
duly acknowledged and recorded.