Valuation of Bonds in a money purchase pension plan

[Guest Bruce Endy]

Does anyone have an opinion on whether it is lawful to value bonds in a money purchase pension plan on an amortized cost basis, not for funding purposes, but for benefit accrual purposes i.e. to value individual participant accounts. If you believe this is OK how do you think Rev. Rul 80-155 affects such a determination. Thank you.