Sorry, I don't know Lacerte.  The original post was in the ProSeries forum.

Forcing it is probably not the answer though, the best bet is usually to have the taxpayer (or spouse) make a deductible retirement or HSA contribution.  The issue likely isn't that Lacerte can't figure out the math, the issue is that you have a math problem with no solution.  Forcing it would be like telling the software that 2 - 2 = 1.