Was the penalty you were assessed perhaps due to late payments? The IRS will assess a penalty for late payments even if the payment amounts are correct.
https://www.irs.gov/businesses/small-businesses-self-employed/estimated-taxes#:~:text=You%20also%20m....
Here is how TurboTax calculates estimated tax payments:
How does TurboTax calculate my estimated tax payments? (intuit.com)
**Answers are correct to the best of my ability but do not constitute tax or legal advice.
