The Internal Revenue Service is trying to give pension plan administrators and others the figures they need to calculate defined benefit plan present values and contribution levels in the coming year.

The IRS published final regulations in February that permit plans to use “blended morality tables” for workers and benefits recipients this year, because of the need to overhaul actuarial systems to cope with the effects of the Pension Protection Act of 2006.

In 2008, the IRS wants to use separate tables for “annuitants” and “nonannuitants,” IRS officials write in a preamble to the proposed morality table regulations, which appear today in the Federal Register.

The IRS uses the term “annuitants” to refer to retirees and the term “nonannuitant” to refer both to terminated vested participants and active workers.

Although using separate tables is more complicated, the IRS and the Treasury Department “believe that failing to project mortality improvement in determining the funding target would tend to result in underfunding,” officials write in the preamble.

The proposed “generally applicable mortality tables” would be based on the RP-2000 Mortality Tables Report, which was developed by the Society of Actuaries, Schaumburg, Ill.

Plan administrators could choose between using a static version of the table and generational mortality tables, which would provide different projected mortality rates for workers of different ages.

Administrators of small plans could continue to use a single blended static table, officials write.

Administrators of some very large plans could use substitute tables.

The IRS plans to create separate tables for disabled plan participants, and it is asking for comments about whether it would be desirable to publish a series of static mortality tables for each of a number of years, such as 5 years, along with the final regulations, and to publish the subsequent tables at a later date.

Comments on the proposed mortality table regulations are due Aug. 27.

A copy of the proposed rule is on the Web