Regular interest shall be credited to a class C member on any deductions erroneously made from the compensation of the member and paid into the annuity savings fund. The interest shall continue until the earlier of:
(1) Refund of the deductions to the member; or
(2) Return of the deductions to the member's employer.
The foregoing shall not require the payment of interest on deductions made from any amounts that exceed the compensation to which a member is entitled.