TurboTax uses AGI and Modified AGI to compute taxable income and Excess Advance Premium tax credit respectively. AGI and Modified AGI can differ especially due to Social Security benefits. When tax due results from "underestimation of AGI and underpayment of taxes" only or "underestimation of modified AGI and Excess Advance Premium tax credit" only consecutively for two years, I understand there will be a tax penalty with 2nd year taxes. In this particular situation, tax due results consecutively for two years because of the same trigger events.
However, there is a possibility that tax due may result consecutively for two years because of two separate trigger events. when tax due results from "underestimation of AGI and underpayment of taxes" only in one year and "underestimation of modified AGI and Excess Advance Premium tax credit" only in 2nd year (or vice versa), will there be tax penalty?
