That portion of any allowance payable because of the death or retirement of any member of such departments which is provided by contributions of the city shall be reduced in the manner fixed by the council, by the amount of any benefits other than medical benefits, payable to or on account of such person, under the Division 4 of the Labor Code of the state of California and because of the injury or illness resulting in such death or retirement. Such portion as is paid because of death or retirement which resulted from injury received in or illness caused by performance of duty, and in the absence of payments of any benefits other than medical benefits under such laws, shall be considered as in lieu of all benefits, other than medical benefits, payable to or on account of such person under such laws, and shall be in satisfaction and discharge of the obligation of the city to pay such benefits. (Prior code § 34.04.406)