Silly question, but how does one settle a Centurion statement? I don't think I have ever seen FedWire instructions for AMEX and most other banks, although I know a few have it. Consumer ACH is risk to AMEX because of possible chargebacks or insufficient funds. These banks normally advance the line as soon as the ACH is initiated, but they really do not have finally settled funds for days or maybe weeks. If your AU was paying via ACH in $100k+ amounts from an unusual financial institution, the risk profile may have been too high for them. Stuff like this is hard for banks to communicate to a customer, so they just drop the account.

A few years ago, I had a courtesy call from Schwab that was along the lines of "If you value your relationship with Schwab, pull back on receiving ACHs and then immediately using the money to pay credit cards. That is all I am really authorized to say." The incoming ACH payments were for hundreds of thousands at the time. He admitted that if I switched to receiving wires, they might be more comfortable.