Interesting. Beneficial ownership is in our CDD procedure which is separate from our CIP procedure.
Anyway, using your scenario, you would likely be criticized for not observing your procedure as your procedure indicates that a change to authorized signers will be considered a triggering event.
Changing authorized signers does not always equate to a change in ownership on a legal entity account. We do not consider it a triggering event unless there is an actual change in ownership. Why create extra work?