Notwithstanding the provisions of section 12-378, an executor or administrator, after filing the return required by section 12-359, together with a proposed computation of the tax payable, and paying the amount of such tax so computed, and after the probate court has approved the final account of such fiduciary, which account shall include a reasonable reserve for additional succession taxes that may be payable, is authorized to distribute, in accordance with the orders of such probate court, such portion of the estate as to which the Commissioner of Revenue Services does not file an objection in such probate court within thirty days after written notice from such fiduciary of the approval of such final account.