Except as otherwise provided in § 4281.16 (regarding plans that are closing out), the plan sponsor must value benefits as of the valuation date by—

(a) Using the interest assumptions under § 4044.54 of this chapter;

(b) Using the mortality assumptions under § 4044.53 of this chapter;

(c) Using interpolation methods, where necessary, at least as accurate as linear interpolation;

(d) Applying valuation formulas that accord with generally accepted actuarial principles and practices; and

(e) Adjusting the values to reflect the loading for expenses in accordance with § 4044.52(d) of this chapter.