I can fill in until Bill arrives. 🙂

Is your AGI near 400% of the Federal Poverty Level (FPL)?

There is a "zone" of income where the PTC/SEHI results in unsolvable math.  I don't know about this year specifically but in prior years that would result in a reduced SEHI deduction and the software seemingly randomly coughing up medical expenses on Schedule A.

Try plugging in a few thousand dollars of IRA contribution and see if your results line up with your expectations.  I have seen cases where the taxpayer can pay $6K of APTC repayment or they can put $3K into an IRA instead.

Rick