Accounts Receivable - Bank Accounts Set Up
Bank set ups are usually done at the highest level (account) unless you have a different ones for each Bill-to. Oracle will look at the Bill-to first, if blank it will read the account level. By setting is up at the account level, there is less maintenance and setups.
The Customer account is at the operating unit level so bank accounts are by operating unit. Therefore updating bank accounts should be set up at the operating level.