For the purpose of determining the benefits calculated under section 2546 and 2547, in the case of annuity contracts under which an election may be made to have annuity payments commence at optional maturity dates, the maturity date shall be deemed to be the latest date for which election shall be permitted by the contract, but shall not be deemed to be later than the anniversary of the contract next following the annuitant's 70th birthday or the 10th anniversary of the contract, whichever is later.   [PL 1979, c. 442, §4 (NEW).]