Special rule in case of certain amendments
In the case of a multiemployer plan which the Secretary of Labor finds to be collectively bargained which makes an election under this subparagraph (in such manner and at such time as may be provided under regulations prescribed by the Secretary), if the full funding limitation determined under section 431(c)(6) for such year is zero, if as a result of any plan amendment applying to such plan year, the amount determined under section 431(c)(6)(A)(ii) exceeds the amount determined under section 431(c)(6)(A)(i), and if the funding method and the actuarial assumptions used are those used for such year under section 431, the maximum amount deductible in such year under the limitations of this paragraph shall be an amount equal to the lesser of—
(i)#
the full funding limitation for such year determined by applying section 431(c)(6) but increasing the amount referred to in subparagraph (A) thereof by the decrease in the present value of all unamortized liabilities resulting from such amendment, or
(ii)#
the normal cost under the plan reduced by the amount necessary to amortize in equal annual installments over 10 years (until fully amortized) the decrease described in clause (i).
In the case of any election under this subparagraph, the amount deductible under the limitations of this paragraph with respect to any of the plan years following the plan year for which such election was made shall be determined as provided under such regulations as may be prescribed by the Secretary to carry out the purposes of this subparagraph.