Could I sneak in a question as to what actuarial table IRC 7520 uses for private annuity calculations (estate tax planning) ? I apologize for the blatant misuse of this forum for non-DB plan purposes and accept my 20 lashes (or more !!).

It is known as the "90CM" table, prescribed by regulation 20.2031-7.

Actually, this is the right forum. Every actuary should have access to this if they ever work on contributory plans that offer partial lump sums. For example, if a participant is allowed to withdraw their after-tax employee contributions (a partial lump sum), the question is, "how much of that is taxable under the pro rata rules of TRA 86?" In Notice 87-13, Q&A 11, the IRS decided that this obscure table is the one that should be used to calculate the total value of the accrued benefit in order to apply the pro rata withdrawal rules. Unfortunately, there are probably fewer than two or three of us in the country that know where to find this table. But that doesn't stop the IRS from making use of it.

Thanks MGB. That was very helpful.