I'm working on my 2020 Federal income return with TurboTax. During the process, a box at the top of my screen shows the tax amount up to the info entered so far. I saw the displaced tax refund amount drops immediately after I entered my $7000 Roth IRA contribution. Then I went back and entered $0 Roth IRA contribution, the tax refund amount went up back as before. I know Roth IRA contribution won't reduced my tax, but it shouldn't increase my tax either. Please explain.
