(A) Provision shall be made for the voluntary retirement of any policeman or fireman member at age 55 years or older, and for any other class or classes of members at age 60 years or older; provided, that in either case the member has ten or more years of credited service; provided, further, that in either case, if the member has 25 or more years of credited service, voluntary retirement may be taken regardless of age.
(B) Provision shall be made for the mandatory retirement of policemen and firemen members at an age not less than 60 years, and for any other class or classes of members, except elected officials of the city, at an age not less than 65 years. Provision shall be made that any member who attains mandatory retirement age may be continued in service provided (1) he request to be continued in service, and (2) his request is approved by his department head and the chief administrative officer of the city. No such continuance in service shall be granted beyond age 72 years or April 1, 1960 whichever is later.