§ 107. Limited return on investment. Subject to the provisions of section one hundred twenty-three of this article, there shall be paid annually out of the earnings of the redevelopment company, after providing for all expenses, taxes and assessments, a sum for interest on and amortization of any mortgage indebtedness and depreciation charges if, when and to the extent deemed necessary by the supervising agency, plus a distribution of six per centum on the capital and interest not exceeding six per centum on outstanding income debentures; except that in the case of redevelopment companies formed prior to April twenty-ninth nineteen hundred sixty, and subject to the provisions of section one hundred twenty-three of this article, there shall be paid annually out of the earnings of the redevelopment company, after providing for all expenses, taxes and assessments a sum for interest amortization, depreciation and distributions, equal to but not exceeding six per centum of the total actual final cost of the project as defined by subdivision two of section one hundred twelve of this article; the obligation in respect of such payments shall be cumulative, and any deficiency in interest, amortization, depreciation and distributions in any year shall be paid either from any cash surplus derived from earnings remaining in the treasury of the redevelopment company in excess of the amount necessary to provide such cumulative annual sums or from the first available earnings in subsequent years; and any cash surplus derived from earnings remaining in the treasury of the redevelopment company in excess of the amount necessary to provide such cumulative annual sums shall, upon the dissolution of, or in the case of a redevelopment company which is a trust the termination of the company, be paid into the general fund of the municipality except as otherwise contemplated by subdivision five of section one hundred twenty-three of this article.