Delinquent Filer Program available?

[Barbara]

Client sponsors a calendar year 401(k) Plan effective 5-1-21. The first two Forms 5500-SF were already filed, but filed late. Subsequent filings were timely.

Client receive Notice CP220 from IRS with huge proposed penalties. (An IRS Notice CP220 tells you that the IRS made changes or corrections to a tax return you or your business filed, resulting in a balance due or an adjusted refund.) No information was provided as to the changes made on the filings, and the filed versions of the Form 5500 matches exactly the version the client signed.

Since this Notice does not refer to late filings, I'm hoping this means that we can still file under DFVC?  What do you all think? There is no indication of any changes IRS proposes to make to the already-filed returns.  I have 3 questions:

1-are we still eligible for DFVC?

2-assuming yes, do we show the original filing dates on the first two filings, or use a current date?

3-how do we respond to the Notice CP220 to get the proposed penalties waived?

[WCC]

The above thread may help. 

Below is information from the DOL. I know the website is not official guidance, but note my highlight, which states that amended filings are not eligible for DFVCP. I am not saying I agree with this position; I am simply pointing it out because I believe this is a new addition to the webpage, or I may not recall seeing it previously.  

https://www.dol.gov/agencies/ebsa/employers-and-advisers/plan-administration-and-compliance/correction-programs/dfvcp