The amounts of net earnings transferable to surplus in any year after making or providing for the payments specified in § 31-1-620 shall be subject to the approval of the director. The amount of such surplus shall not exceed fifteen percent of the outstanding capital stock and income debentures of the corporation, but the surplus so limited shall not be deemed to include any increase in assets due to the reduction of a mortgage or amortization or similar payments. On dissolution of any limited dividend housing corporation the stockholders and income debenture certificate holders shall in no event receive more than the par value of their stock and debentures plus accumulated, accrued and unpaid dividends or interest and any remaining surplus shall be paid into the general fund of the State.