I do exactly the same as abctax.  Back in the old "50% penalty" days, I never had a waiver request denied.  ProSeries has a place to write text for the waiver (I assume Lacerte has something similar) and "RC" should appear next to box 54.  I always state that it was an error due to [DarnGoodReason], it was corrected and a distribution was made on x/x/yy for the missed RMD.

Now that the penalty is "only" 25% AND there's a 10% penalty "correction period" I suspect the IRS will more actively reject reasonable cause (RC) waivers.  It's too early to tell but unless/until the IRS changes the 5329 form/instructions, I plan to continue using the RC waiver method if I think my client qualifies.

Read through the Part IX instructions on pages 8-9:

https://www.irs.gov/pub/irs-pdf/i5329.pdf

Rick