Thanks. That makes sense. I did something similar with the What-if, but didn't do a mock simulated return first. Instead, I brought up my completed 2019 tax return and accessed the What-if form. It automatically populated Column 1 with my 2019 tax return. I then copied Column 1 to Column 2, and checked the box for "use 2020 rates" for Column 2. Then I manually went into Column 2 entries and changed the data for estimated 2020. The main one I was concentrating on was Line 15b "Taxable IRA Distribution" for my various Roth conversion amounts. I'm kind of reluctant to do the simulated return as I remember the questions for IRA's got tedious with situations that didn't apply to me.
One more question, once you calculate your tax liability, do you add a cushion to it (i.e., % or flat amount) "just in case" to avoid a tax underpayment? I know I will have to file the 2210 to show the 4th quarter income generated by the Roth conversion.
