Is there any regulatory requirement that indicates banks must post "real-time"?

For UDAP purposes can batch processing be considered unfair?

For example:
Assessing an overdraft fee based on the available balance at the time a transaction is posted when there were sufficient funds in the available balance to cover the transaction when it was authorized. How do you get around this under batch processing?

Our core implemented a piece that will not assess an overdraft fee if a debit card transaction is approved on good funds if additional transactions clear before it does. Check with your core provider. Before that, we manually reviewed reports daily of overdrawn accounts and waived overdraft fees on transactions that were approved on good funds.

We switched from available balance OD processing to ledger balance processing.