@Intuit_Ruben 

The question is 'why' Lacerte can't do the actual math of limiting the NOL deduction to 80% of income. 

It is a similar computation of the SEHI deduction; when there are income amounts that are partially taxable based on income (example = SS benefits) the computation becomes 'circular'.  

Lacerte IS able to do it for SEHI, altho a diagnostic is generated.

It seems Lacerte, for what it costs, could do the programing for the NOL/80% calculation also....