Thank you.  I had phrased my prior response poorly and maybe I'm still wrong, but are you sure it is calculated "before" the NOL, rather than "without" the NOL?

My point is things like Social Security and AGI-based deductions.

Do you start with 80% of taxable income and then permanently stop?

Or do you start with 80% of taxable income, then see the amount of taxable Social Security or other AGI-based deductions changes the taxable income (not counting the NOL) and need to re-figure the 80%, which in turn will adjust things again.  That is what I was referring to when I mentioned the Iterative calculation.  I've seen other posts that indicate that is what needs to be done, but maybe I'm wrong.