Amend 5500 and Attach Audit for Prior Years?

[jukeboy56]

Subject company has filed 5500 as a small plan for 2013, 2014 and 2015.

They recently discovered that a division of the company was not offered the opportunity to participate in those years. 

The company has done a self-correction for the failure to cover those employees.

If participant counts had correctly included the missed employees the plan would have been considered a large plan for 2013, 2014 and 2015.

Should the company file amended 5500's for 2013, 2014 and 2015 and hire an independent auditor to audit the Plan for those years?

This doesn't fit any fact patterns described in the voluntary correction programs, so how should they proceed?

[Belgarath]

Others may have different opinions, but without doing any research or analysis, my gut reaction is to file amended returns (with the audit, of course).

[RatherBeGolfing]

I agree, amend and file with audit.

[WillSanDiego CPA]

Agree, file amended returns but use the VFDC (https://www.irs.gov/retirement-plans/irs-penalty-relief-for-dol-dfvc-filers-of-late-annual-reports ) where the penalty can be capped at $2,000 for the multiple being late with multiple years.  Also the program allows the penalties to be abated.