Hello. Last year we filed using a far inferior software program (hint, it starts with HR and ends with Block), and checked the box for safe harbor estimated taxes. We paid 110% of our 2020 income in estimateds on time for all four 2021 quarterly periods. When later in 2021 that it became apparent that our income was going up by more than 110%, we paid extra in Q4. The extra amount didn't get us all the way caught up, and TurboTax is now saying I owe more than $500 in underpayment penalties. I thought that by electing safe harbor we were shielded from penalties in the event of an underpayment. Is there anything we can do? Please let me know. Thank you!
