412(e)(3) plan conversion

I have a prospect that wants to convert their 412(e)(3) plan into a traditional defined benefit.  I've never done this and the only way I can see when I read the ERISA outline book is to ask the IRS to treat the plan as if it was never a fully-insured plan.  I calculate funding minimums and maximums back to plan effective date.  If the contributions fall in the range and I do everything else the examining agent asks, then it would be "converted" or in other words, it was never a fully-insured plan.

Anyone ever done this?  Please share your experience, strength, and hope.

Why not just amend and restate the plan effective with the most logical date (probably 1/1/2018) establishing the 1/1/2018 accrued benefit in accordance with the existing plan and then go forward from there?

It's a 4/1 plan so I can restate 4/1.  On the 5500, I now uncheck the box that says it's a 412(e) plan and start doing SB's?  Keep annuity contracts as paid up contracts.  Check that insurance still satisfies incidental benefit rules.  Seems too easy to be true. 

Some things are just that easy.