Anything contained in this title to the contrary notwithstanding, the benefit payable to or on account of a group C member hereunder, inclusive of any benefit provided by his additional contributions as specified in subsection 473(b) of this title together with the Social Security benefit or survivor's insurance benefit, as the case may be, shall not be less than the benefit which would have been payable to him or her or on his or her account under the provisions of the Vermont State Police and Motor Vehicle Inspectors' Retirement System as in effect on June 30, 1972 had said System continued in effect unamended. (Added 1971, No. 231 (Adj. Sess.), § 4.)