This section does not apply to industrial policies issued on or after the operative date of § 38-63-600 as defined therein. All adjusted premiums and present values referred to in this article must, for policies of industrial insurance issued prior to January 1, 1968, be calculated on the basis of either the 1941 Standard Industrial Mortality Table or the Commissioners’ 1961 Standard Industrial Mortality Table as may be elected by the insurer and approved by the Secretary of Commerce or his designee. However, adjusted premiums and present values for all policies of industrial insurance issued on or after January 1, 1968, must be calculated on the basis of the latter table. All calculations must be made on the basis of the rate of interest specified in the policy for calculating cash surrender values and paid-up nonforfeiture benefits so long as the rate of interest does not exceed three and one-half percent per annum, except that a rate of interest not exceeding four percent per annum may be used for policies issued on or after January 3, 1976, and prior to January 1, 1979, and a rate of interest not exceeding five and one-half percent per annum may be used for policies issued on or after January 1, 1979, except that for any single premium whole life or endowment insurance policy a rate of interest not exceeding six and one-half percent per annum may be used. However, in calculating the present value of any paid-up term insurance with the accompanying pure endowment, if any, offered as a nonforfeiture benefit, the rates of mortality assumed may be not more than one hundred thirty percent of the rates of mortality according to the 1941 Standard Industrial Mortality Table, if this table is used for calculating adjusted premiums and present values, or more than those shown in the Commissioners’ 1961 Industrial Extended Term Insurance Table, if the Commissioners’ 1961 Standard Industrial Mortality Table is used for calculating adjusted premiums and present values. For insurance issued on a substandard basis, the calculation of adjusted premiums and present values may be based on any other table of mortality as may be specified by the insurer and approved by the Secretary of Commerce or his designee.