(7) Defined benefit plan exception In determining the amount of nondeductible contributions for any taxable year, an employer may elect for such year not to take into account any contributions to a defined benefit plan except, in the case of a multiemployer plan, to the extent that such contributions exceed the full-funding limitation (as defined in
section 431(c)(6)). For purposes of this paragraph, the deductible limits under
section 404(a)(7) shall first be applied to amounts contributed to defined contribution plans and then to amounts described in this paragraph. If an employer makes an election under this paragraph for a taxable year, paragraph (6) shall not apply to such employer for such taxable year.