I halted the assembly line yesterday and just started doing triage.  I've been plucking things out of the queue that might need attention before 4/15.  Definitely anyone who typically has ES payments.  I have a few who are on/off ES depending on how their investments do each year so I'll need to check their safe harbor numbers.

I also had one who needed a 401(k) corrective distribution.  Best I can tell that deadline has NOT been extended for correction of excess deferrals under section 402(g)(2).  Seems to be set by statute rather than tied to the 1040 due date and was NOT on the short list of things Chuck agreed to extend.

I've had two terrible experiences with Voya this year.  I will never voluntarily do business with them again (although you can't usually pick who an employer uses for retirement).  Supposedly they're fixing my client's 401k excess on Thursday 4/8.  I'll believe it when I see it, we've been trying since mid-February.  If they think they fixed it now, I'm not sure why it will still take a week.  If you have clients who deal with Voya, they need to keep hounding them.  The company doesn't seem to actually follow-through with anything on their own.