All applications for retirement, whether for service or for disability, must be filed not more than 90 days prior to the date specified by the member as the effective date of his or her retirement; the date specified as the effective date for retirement must be the last day of a calendar month and may not be a date preceding the termination of the member's employment with all participating municipalities. An application is filed when it is actually received at the office of the director of the system in Austin.