Correcting for missed Opportunity for Voluntary After-Tax

[Loves401(k)]

I have a plan with several hundred people that allows Voluntary After-tax.  I am trying to write a procedure for fixing payroll errors involving Voluntary After-tax Contributions.  I have found good guidance for fixing when an election form is misplaced.  But I cannot find any written guidance on what to do when an eligible employee was not given the opportunity to have Voluntary After-Tax contributions deducted from his check.

What do you all think?

Use the average of the NCE/NHCE group for the year?

[Madison71]

The correction is in Rev. Proc. 2016-51. A QNEC to the plan on behalf of the employee equal to the missed opportunity for making an after-tax employee contribution.  The missed opportunity is equal to 40% of the employee's missed after-tax contribution.  The employee's missed after-tax is equal to the ACP for the employee's group, not to exceed plan limits.  The QNEC must be adjusted for earnings.