Hi Bryan
I would maintain the change in the Org Structure, with effect from the new cost centre validity date (cost centre either assigned at Org Unit inherited to all Positions or at Position level individually if the change does not apply to all).
To ensure the new cost centre change is valid in PA master data only from the expected date, also run Personnel Actions to record the Org Reassignment/Change from the effective date via PA40.
Best regards,
Alison