The estimated penalty is calculated by the program using the information YOU provided and the state calculates the penalty using the info they have on file for you which may not be the same.  When you actually filed and paid the balance due also comes into play.    You may have indicated to skip the estimated penalty calculation in the state interview. 

And even if the program did add an estimated penalty the feds/state always have the right to access more penalties and interest.  

@Critter-3: I appreciate the feedback. However, I e-filed my VA return (with direct debit payment) the same day that I e-filed my Federal return (before the filing deadline), so I don't believe that timing of the return is an explanation. (Also, VA did not charge me any interest -- just the under-withholding penalty.)

If the VA tax authority calculated a penalty using the information filed, then TT needs to incorporate that calculation into its VA state return logic. I would like Intuit to investigate this issue; either the VA State product needs updating, or else VA improperly assessed my penalty.

FYI, I see a separate posting that suggests that TT has a related problem with its NY state return product.

Just a thought - did the program have your information from the preceding tax year?  It needs that info to determine whether or not you are liable for an underpayment penalty.

@TomD8 : Yes - I have been using TT Deluxe with State for years. The program had access to my prior year's returns, since it transferred that info when I started my 2020 return.