Effective September 1, 1947, the retirement allowances of retired Ohio teachers, or their beneficiaries under options elected at retirement and still in effect, on the retired list as of that date shall be recalculated and paid in accordance with the following:

(A) Members retired on superannuation effective prior to August 31, 1945, shall have the prior service portion of their allowances recalculated as of the date of retirement in accordance with division (C) of former section 3307.38 of the Revised Code, with their “final average salary” determined as defined in former section 3307.01 of the Revised Code. Any allowance payable to members who retired on superannuation under an option selected at retirement, or payable to a beneficiary pursuant to such option, shall be adjusted upon the basis of the amount of allowance payable in accordance with this division.

(B) Members retired on disability retirement prior to July 1, 1945, shall have their allowances recalculated as of the date of retirement in accordance with divisions (A) and (B) of former section 3307.43 of the Revised Code, and with their final average salaries determined as defined in former section 3307.01 of the Revised Code.

(C) Members retired on superannuation, commuted superannuation, or disability prior to June 30, 1947, with fifteen or more years of service credit shall receive a total allowance at the rate of not less than twenty dollars annually for each year of such service credit, except that a member retired on commuted superannuation shall have the reserve for any additional pension required to provide such minimum allowance commuted as of the date of retirement in the manner prescribed for the prior service pension in former section 3307.40 of the Revised Code. Any allowance payable to members who retired on superannuation under an option selected at retirement, or payable to a beneficiary pursuant to such option, shall be adjusted upon the basis of the amount of allowance payable in accordance with this division. All pensions continued to pensioners following the merger of local district pension systems with the state teachers retirement system pursuant to former sections 3307.68, 3307.69, and 3307.70 of the Revised Code shall be increased ten dollars per month provided no other benefit is payable by this section.

(D) In no case shall any recalculated allowance be increased in excess of twenty-five dollars per month by divisions (A), (B), and (C) of this section and in no case shall any allowances be decreased thereby. In no case shall any such increases be payable prior to September 1, 1947. The cost of providing such increased superannuation and commuted superannuation allowances shall be included in the prior service pension deficiency contribution rate provided for in former section 3307.54 of the Revised Code. The cost of providing such increased disability allowances shall be included in the normal contribution rate provided for in section 3307.28 of the Revised Code.