Missed Deferrals and Confirmation of Corrections

I have a calendar year plan with auto enrollment that missed auto enrolling certain new hires in 2016, 2017, 2018. The plan has 3 month eligibility for deferrals and  match. The auto enrollment % is 5%.

I have reviewed Rev. Proc 2015-28 and the IRS Fix It Guide and there are a couple of variations. I want to make sure all the facts are in order. For example the Fix Guide mentions fixing the failure promptly and also that in order for the reduced QNEC to apply, the employee cannot be terminated - if terminated then the 50% QNEC rule applies.

Here are my views and corrections on these missed deferrals and match based on this guidance:

1. 2016 failures - they did not get corrected by 10/15/17 (9 1/2 months after the end of the plan year in which the failure occurred) so the QNEC is 25% of the 5% missed deferrals to date(?), plus earnings, and 100% of the full 5% match.  The deferrals will get started by 3/9 the next payroll period, the notice will go out within the next week. The corrective contributions and earnings (through date of correction) will be calculated and posted as soon as possible. Did I miss anything?

2. 2017 failures  - as illustrated in the IRS Fix It Guide Example 2, no QNEC is due for the missed contributions during 2017. And for 2018, no QNEC is due for missed deferrals, since we are in the first 3 months. However the missed match is due plus earnings. The deferrals will now be started at 5% by 3/9 the next payroll period, and they will get a notice within the next week.

3. 2018 failures - no QNEC is due since we are in the first 3 months, but any missed match is due. The notice will go out and deferrals will start on the 3/9 payroll.

For any terminated employee, if a QNEC is due for missed deferrals is it 50%? What about for 2018 during the first 3  months, do we get a pass? Example 4 in the Fix It guide has illustration for a terminated employee - a 50% QNEC is due since none of the safe harbors apply.

Sorry for the lengthy fact pattern, hopefully it reads quickly!

Thank you for any help!

rp-15-28.pdf

401k-plan-fix-it-guide-eli.pdf