how did pay the tax was it estimated tax and paid evenly through the year, or did you pay it unevenly?
you can meet the 110% in total for the year to, but if you didn't do it evenly you may be assessed a penalty for underpayment in a particular quarter.
are you on desktop or online. if on desktop in Forms mode you can double-click on Form 1040 penalty amount then double click again on the penalty in the worksheet and you will get to Form 2210 which will show you the calculations. Not sure equivalent with TT Online, if you're able to see a copy of the return with 'all forms and worksheets' it might be in there.
