(a) Each policy or policies purchased under section 1966 of this title shall include for the first policy year a schedule of basic premium rates by age which the Secretary shall have determined on a basis consistent with the lowest schedule of basic premium rates generally charged for new group life insurance policies issued to large employers, this schedule of basic premium rates by age to be applied, except as otherwise provided in this section, to the distribution by age of the amount of group life insurance under the policy at its date of issue to determine an average basic premium per $1,000 of insurance. Each policy so purchased shall also include provisions whereby the basic rates of premium determined for the first policy year shall be continued for subsequent policy years, except that they may be readjusted for any subsequent year, based on the experience under the policy, such readjustment to be made by the insurance company or companies issuing the policy on a basis determined by the Secretary in advance of such year to be consistent with the general practice of life insurance companies under policies of group life insurance issued to large employers.

(b) The total premiums for Servicemembers' Group Life Insurance shall be the sum of the amounts computed according to the provisions of subsection (a) above and the estimated cost traceable to the extra hazard of active duty in the uniformed services as determined by the Secretary, subject to the provision that such estimated costs traceable to the extra hazard shall be retroactively readjusted annually in accordance with section 1969(b).

(c) Each policy so purchased shall include a provision that, in the event the Secretary determines that ascertaining the actual age distribution of the amounts of group life insurance in force at the date of issue of the policy or at the end of the first or any subsequent year of insurance thereunder would not be possible except at a disproportionately high expense, the Secretary may approve the determination of a tentative average group life premium, for the first or any subsequent policy year, in lieu of using the actual age distribution. Such tentative average premium rate shall be redetermined by the Secretary during any policy year upon request by the insurance company or companies issuing the policy, if experience indicates that the assumptions made in determining the tentative average premium rate for that policy year were incorrect.

(d) Each policy so purchased shall contain a provision stipulating the maximum expense and risk charges for the first policy year, which charges shall have been determined by the Secretary on a basis consistent with the general level of such charges made by life insurance companies under policies of group life insurance issued to large employers. Such maximum charges shall be continued from year to year, except that the Secretary may redetermine such maximum charges for any year either by agreement with the insurance company or companies issuing the policy or upon written notice given by the Secretary to such companies at least one year in advance of the beginning of the year for which such redetermined maximum charges will be effective.

(e) Each such policy shall provide for an accounting to the Secretary not later than ninety days after the end of each policy year, which shall set forth, in a form approved by the Secretary, (1) the amounts of premiums actually accrued under the policy from its date of issue to the end of such policy year, (2) the total of all mortality and other claim charges incurred for that period, and (3) the amounts of the insurers' expense and risk charge for that period. Any excess of the total of item (1) over the sum of items (2) and (3) shall be held by the insurance company or companies issuing the policy as a special contingency reserve to be used by such insurance company or companies for charges under such policy only, such reserve to bear interest at a rate to be determined in advance of each policy year by the insurance company or companies issuing the policy, which rate shall be approved by the Secretary as being consistent with the rates generally used by such company or companies for similar funds held under other group life insurance policies. If and when the Secretary determines that such special contingency reserve has attained an amount estimated by the Secretary to make satisfactory provision for adverse fluctuations in future charges under the policy, any further excess shall be deposited to the credit of the revolving fund established under section 1969(d)(1) of this title. If and when such policy is discontinued, and if after all charges have been made, there is any positive balance remaining in such special contingency reserve, such balance shall be deposited to the credit of the revolving fund, subject to the right of the insurance company or companies issuing the policy to make such deposit in equal monthly installments over a period of not more than two years.