Each member shall keep the credit union informed of his current address. In the event a member fails to do this, a charge may be made to the member’s share account for the actual cost of necessary locator service incurred in determining such an address; provided, however, that such charge shall not exceed five dollars ($5). Such charge shall be made only for amounts paid to a person or concern normally engaged in providing such service and shall be made against the account or accounts of any one member no more than once in any 12-month period.