Thanks @dmertz, I confirmed that increasing the net profit to $22,411 (by decreasing my expenses by $1) causes TurboTax to correctly calculate the maximum Individual Retirement Plan Contribution as $22,500. But isn't this perverse? For all of TurboTax's grandiose claims of 100% Accuracy blah-blah-blah, the best advice is that I should "fudge" my numbers in order to get TurboTax to do the right thing? I realize this is an edge case, but edge cases are where software bugs so often show up.
