In the case of an individual entitled to monthly insurance benefits payable under this section for any month prior to January 1973 whose benefits were not redetermined under section 102(g) of the Social Security Amendments of 1972, such benefits shall not be redetermined pursuant to such section, but shall be increased pursuant to any general benefit increase (as defined in section 415(i)(3) of this title ) or any increase in benefits made under or pursuant to section 415(i) of this title , including for this purpose the increase provided effective for March 1974, as though such redetermination had been made.