This section shall apply to only those policies and contracts issued prior to the operative date defined in section 44-407.07 (the Standard Nonforfeiture Law for Life Insurance). All such valuations made by the Department of Insurance, or by its authority, shall be according to the standard of valuation adopted by the company, which standard shall be stated in its annual report to the department. Such standard of valuation, whether on the net level premium, preliminary term, any modified preliminary term, or select and ultimate reserve basis, for all such policies issued after July 17, 1913, shall be according to the American Experience or Actuaries' Table of Mortality, with not less than three and not more than four percent compound interest. When the preliminary term basis is used it shall not exceed one year. Insurance against total and permanent mental or physical disability resulting from accident or disease, or against accidental death, combined with a policy of life insurance, shall be valued on the basis of the mean reserve, being one-half of the additional annual premium charged therefor. Except as otherwise provided in subdivision (b) of section 44-404 for all annuities and pure endowments purchased on or after the operative date of such subdivision (b) under group annuity and pure endowment contracts, the legal minimum standard for the valuation of annuities shall be McClintock's Table of Mortality Among Annuitants, or the American Experience Table of Mortality, with compound interest at three and one-half percent per annum for individual annuities and five percent per annum for group annuities, but annuities deferred ten or more years, and written in connection with life or term insurance, shall be valued on the same mortality table from which the consideration or premiums were computed, with compound interest not higher than three and one-half percent per annum. The legal standard for the valuation of industrial policies shall be the American Experience Table of Mortality, with compound interest at not less than three nor more than three and one-half percent per annum; PROVIDED, any life insurance company may voluntarily value its industrial policies written on the weekly payment plan according to the Standard Industrial Mortality Table or the Substandard Industrial Mortality Table. Reserves for all such policies and contracts may be calculated, at the option of the company, according to any standards which produce greater aggregate reserves for all such policies and contracts than the minimum reserves required by this section.