The allowances that commenced to accrue prior to July 1, 1972, and payable on August 1, 1972, exclusive of annuities from the Annuity Deposit Fund and tax-sheltered annuities payable under former Sections 14193, 14280 and 14284, as those sections read on June 30, 1972, shall be increased by application of the benefit improvement factor on September 1, 1973, and annually thereafter.