The board may at any time that it appears desirable and advantageous, contract with any recognized and solvent legal reserve life insurance company for the payment of any benefits specified in this Article, provided such contract applies alike to all persons of the same class and does not cause any discrimination or create conditions which will substantially limit or reduce the equity or security of any other participant or annuitant in the system at the time. If any such contract is entered into, the board may certify vouchers for the payment to any such contractor out of funds belonging to this system of the amounts payable under such contracts.