TT calculates an estimated underpayment
penalty based on your entries in the program however the feds & state
reserve the right to access a final underpayment penalty, late
filing penalty or late paying penalty ( plus interest ) based on the info they
have and when the balance due was actually paid.
https://www.irs.gov/individuals/understanding-your-cp14-notice
For instance, if the
2017 program said you should pay $1000 a quarter and you transferred in that
info to the 2018 program then the program calculates the penalty on the $1000 a
quarter you were supposed to pay ... however if you did not pay those payments
timely and did not correct the program's
assumption that you did (maybe you missed the april payment but caught up on
the june payment ... or paid it all on one payment in January) then the fed/state know this and
made the correction and billed you accordingly.
To see whether a payment has posted or view your overall
balance, you can use the Get Transcript tool to request a Tax Account
Transcript or Record of Account Transcript.
