(a) In general. A plan must disregard the following nonforfeitable benefit reductions and benefit suspensions in determining a plan's nonforfeitable benefits for purposes of determining an employer's withdrawal liability under section 4201 of ERISA:

(1) Adjustable benefit. A reduction to adjustable benefits under section 305(e)(8) of ERISA and section 432(e)(8) of the Code.

(2) Lump sum. A benefit reduction arising from a restriction on lump sums or other benefits under section 305(f) of ERISA and section 432(f) of the Code.

(3) Benefit suspension. A benefit suspension under section 305(e)(9) of ERISA and section 432(e)(9) of the Code, but only for withdrawals not more than 10 years after the end of the plan year in which the benefit suspension takes effect.

(b) Simplified methods. See § 4211.16 for simplified methods for meeting the requirements of this section.