Each applicable limitation provided by section
404
(a) shall be determined as if all participants in the plan were employed by a single employer. The amounts contributed to or under the plan by each employer who is a party to the agreement, for the portion of his taxable year which is included within such a plan year, shall be considered not to exceed such a limitation if the anticipated employer contributions for such plan year (determined in a manner consistent with the manner in which actual employer contributions for such plan year are determined) do not exceed such limitation. If such anticipated contributions exceed such a limitation, the portion of each such employer’s contributions which is not deductible under section
404 shall be determined in accordance with regulations prescribed by the Secretary.