(1) All bonds or other evidences of debt having a fixed term and rate of interest held by an insurer may, if amply secured and not in default as to principal or interest, be valued as follows:
(a) If purchased at par, at the par value.
(b) If purchased above or below par, on the basis of the purchase price adjusted so as to bring the value to par at maturity and so as to yield in the meantime the effective rate of interest at which the purchase was made, or in lieu of such method, according to such accepted method of valuation as is approved by the commission.
(c) Purchase price shall in no case be taken at a higher figure than the actual market value at the time of purchase, plus actual brokerage, transfer, postage, or express charges paid in the acquisition of such securities.
(2) The office shall have full discretion in determining the method of calculating values according to the rules set forth in this section, but no such method or valuation shall be inconsistent with the method formulated or approved by the National Association of Insurance Commissioners or its successor organization and set forth in the latest edition of its publication “Valuation of Securities”; provided that such valuation methodology is substantially similar to the methodology used by the National Association of Insurance Commissioners in its July 1, 2002, edition of such publication. Amortization of bond premium or discount must be calculated using the scientific (constant yield) interest method taking into consideration specified interest and principal provisions over the life of the bond. Bonds containing call provisions shall be amortized to the call or maturity value or date that produces the lowest asset value.