Determining present value of synthetic equity for 409(p)

[Guest tmills]

Non-qualified deferred comp. plans are to be converted to synthetic equity by using their "present value" and the current S Corp stock price. Does anyone have a clue what interest rates are to be used to determine present value? Here is one example. HCE has an arrangement whereby the company is to deposit $6250/quarter into the plan. This continues to age 60. At that point HCE can take 60 monthly w/drawals until the account is gone. The money is going into an annuity product w/ multiple investment options that the HCE can switch between. Of course it is possible that the present value is simply the current accumulated value of the account, but I don't see anything helpful in the regs. If that is the case, how would a different plan that promises $50,000/yr for 10 years starting at age 60 be valued if nothing has been set aside for it?

Any thoughts would be appreciated.