on the ES for 2025, TT will generate vouchers by default based on paying 100% of 2024 tax (or 110% if AGI > 150k) and based on 2024 withholding level, unless you go through the Estimated Tax section and provide estimates for 2025 to figure that "90% of 2025 tax" will be lower 'safe harbor' threshold to meet. I'm not familiar with H&B myself but I assume that's under Other Tax Situations the same as other desktop versions.
In Forms mode if you double-click on the penalty line in the Form 1040 then double-click it again in the worksheet it should bring up the Form 2210 to show the calculations. I don't know if there is a way to figure out how IRS came to a different result - TT should be using the same calcs on Form 2210 that the IRS uses, unless one of the experts here can explain what the IRS is adjusting or doing differently.
I am wondering if IRS has different dates for your estimated tax payments which could affect the penalty calculation. I just checked the payment history under my account for 2024 (on irs.gov), as far as I knew I paid Q3+Q4 ES on time, but IRS has recorded them a day late, so I wonder if that will affect the calcs and I'll get a penalty adjustment. Making a note to pay a day early for 2025!
