With all the new adjustments this year handled on Schedule 1-A (No Tax on Tips, No Tax on Overtime, and the Enhanced Deduction for Seniors), the IRS's way of dealing with them on 2210 Schedule AI was to tell you to just adjust for them when going from Line 13 which is essentially your annualized taxable income before the Schedule 1-A and Line 14 which is the annualized income tax (from the instructions for Line 14: "You may adjust your 2025 taxable income here for any provision you did not account for elsewhere on Form 2210 before calculating your 2025 tax subject to underpayment of estimated income tax. Schedule 1-A (Form 1040) 2025 provides for new additional deductions for qualified tips, qualified overtime compensation, qualified passenger vehicle loan interest, and the enhanced deduction for seniors." FreeTaxUSA is making no adjustment here and ignoring that my wife and I qualify for th enhanced senior deduction; consequently, the amount it calculates was due each quarter is higher than it should be.
Since I'm new to FreeTaxUSA this year, I'm running a side-by-side comparison with my old tax software. My old tax software is getting it right. As an example, both my old software and FreeTaxUSA have $98,664 on line 13 for Q1 but for Line 14 (annualized income tax) my old software has $9,918 while FreeTaxUSA has $11,537 with that difference being that my old software is deducting the enhanced senior deduction (per the IRS instructions quoted above) while FreeTaxUSA is not.