MDO in Tax-Exempt 457b Plan

Client forgot to enroll an eligible employee and has missed deferrals in a tax exempt 457(b) plan that the employer participates in. My understanding is that, since there is limited opportunity to submit corrections to the IRS under Section 4.09 of EPCRS, that practitioners interpret that to mean that corrections for 457(b) plans can generally follow those prescribed under EPCRS for qualified plans. So in this case we would corrective contributions for the participant's missed opportunity to make a contribution/invest (e.g., 50% of missed deferral) as under EPCRS.