......I still think y'all are focusing on the wrong thing.
He owed a balance due of $1667, which if far above the $500 MD has as one of the safe harbor situations MD allows for not owing underpayment interest. The one cent is just an annoyance, the main issue is the "underpayment" charge of $69 due to exceeding that $500 final bill....and apparently not attempting to minimize it with a form 502UP.
But the details of exactly when this user ( @mjfkak ) actually paid his final bill, and whether he prepared & filed a 502UP at all, have not been established, so the $69 bill may be entirely proper.
____________*Answers are correct to the best of my knowledge when posted, but should not be considered to be legal or official tax advice.*
