If an employer, or in the case of a multi-employer plan, 10 percent or more of the number of employers contributing to or under the plan are unable to satisfy the minimum funding standard for a plan year without temporary substantial business hardship (substantial business hardship in the case of a multiemployer plan) and if application of the standard would be adverse to the interests of plan participants in the aggregate, the Secretary of the Treasury may waive the requirements of section
1082
(a) of this title for such year with respect to all or any portion of the minimum funding standard other than the portion thereof determined under section
1082
(b)(2)(C) of this title. The Secretary of the Treasury shall not waive the minimum funding standard with respect to a plan for more than 3 of any 15 (5 of any 15 in the case of a multiemployer plan) consecutive plan years. The interest rate used for purposes of computing the amortization charge described in subsection (b)(2)(C) of this section for any plan year shall be—