I look at the TurboTax Deluxe (2025) running Federal Refund / Owed display window on the top banner of the desktop version all the time while I'm making changes. When I added my SSA benefit, the Federal Owed display window applied a 20% tax on the added income. I'm in the 22% tax bracket (which adding in the SSA income does not change), but my effective tax rate is around 13%. Is that normal? I did play with my income order and my impression was that whatever I added last usually resulted in a higher applied tax rate on that income.
