Did ProSeries cough up a hairball (and leave it lying on the Sch A Medical Wks)?

There are certain circular calculations involving PTC/SEHI that are unsolvable.  If a deductible IRA is available I would try plugging some numbers into that to see if the software can find a solution.  Unfortunately trial-and-error is the easiest approach, just keep plugging numbers into the IRA box and see what happens.