(a) Each member of tier II who has attained age sixty-five and has completed ten or more years of vesting service may retire on his own application on the first day of any future month named in the application. Benefits shall be payable from that date provided the member is no longer in state employment.

(b) Each member of tier II who has attained age seventy and has completed five or more years of vesting service shall be retired on the first day of the month coincident with or, otherwise, immediately following his seventieth birthday, except as provided in subsection (e) of this section.

(c) Each member of tier II referred to in subsections (a) and (b) of this section shall receive a monthly retirement income beginning on his retirement date equal to one-twelfth of one and one-third per cent of his final average earnings plus one-half of one per cent of his final average earnings in excess of the year’s breakpoint, the sum multiplied by the number of years of his credited service and fractions thereof. The year’s breakpoint for a member shall be conclusively determined based upon the calendar year in which occurred the last severance from service of the member. If a member has more than one severance from service date due to reemployment, such reemployment cannot result in a smaller benefit than would have been payable had he not been reemployed. Notwithstanding any other provision of sections 5-192e to 5-192x, inclusive, to the contrary, if a member’s date of retirement, disability, death or termination occurs in the first six months of any calendar year, his monthly retirement income shall in no event be less than that which would have been payable had his date of retirement, disability, death or termination occurred as of December thirty-first of the prior year, and had his final average earnings, credited service, and breakpoint been determined as of that date. No retroactive payments shall be paid because of such minimum, and his actual date of retirement, disability, death or termination shall be utilized for all other purposes of the tier II plan.

(d) For each member referred to in subsections (a) and (b) of this section who has completed twenty-five or more years of vesting service, the monthly retirement income shall be the greater of the amount calculated under subsection (c) of this section or (1) if retirement occurs before July 1, 1983, $200; (2) if retirement occurs on or after July 1, 1983, and on or before June 30, 1984, $220; (3) if retirement occurs on or after July 1, 1984, and on or before June 30, 1985, $240; (4) if retirement occurs on or after July 1, 1985, and on or before June 30, 1986, $260; (5) if retirement occurs on or after July 1, 1986, and on or before June 30, 1987, $280; (6) if on or after July 1, 1987, $300.

(e) Retirement on the first day of the month on or after the member’s seventieth birthday is mandatory regardless of whether he is eligible for a retirement income under this section except:

(1) A department head, as defined in § 4-5, or any commissioner appointed to office in the executive branch by the Governor with or without the approval of the General Assembly or either branch thereof, who reaches his retirement date, namely, the first day of the month on or after his seventieth birthday, during the term for which he is appointed, may continue in office after such retirement date until the expiration of such term. Any such person who had reached such date prior to his reappointment as such commissioner may serve for the term for which he is so reappointed.

(2) A member who has reached the retirement age of seventy may be continued in his position in state service, if such continuation is approved by the Commissioner of Administrative Services. The appointing authority requesting such continuation shall certify in writing to the Commissioner of Administrative Services that the continuation is desirable for the efficient conduct of the state’s business and that the member is able and qualified to perform the work required. Approval by the Commissioner of Administrative Services of such continuation shall be for a period of one year, which may be renewed by said commissioner upon request by the appointing authority.

(3) A member who is a teacher, instructor, principal, superintendent, or supervisor employed by the State Board of Education or any state institution, and who has reached the retirement age of seventy may be continued in his position of state service to the end of the fiscal year in which his seventieth birthday falls, without the approval of the Commissioner of Administrative Services.

(4) A department head, head of an institution, or administrator of a state fund may be continued as provided in subdivision (2) of this subsection. A continuation of such employee beyond the age of seventy-three shall be requested by the appointing authority in writing and shall require the approval of the Governor.

(5) A duly appointed and acting messenger or assistant messenger of any constituent court of the Judicial Department who has reached his retirement age of seventy may be reemployed, pursuant to § 51-78, in the service of the court in which he has been a messenger at the salary paid him at the time of his retirement. Such reemployment shall continue until such time as the judges of said court terminate the same. Subdivision (2) of this subsection does not apply to any such messenger.

(6) Except as provided in § 5-192v, the existing retirement rights of a member continued under this section after his retirement date shall not be affected by such continuation, and additional retirement rights shall accrue to him. The provisions of chapter 67 dealing with examinations, certifications, and appointments to and separations from the service shall not apply to any such member.