It seems to be based on how much money I have *ever* taken out of any traditional IRA, vs the amount that I have ever paid MA tax on? And what does it mean to have paid MA tax when I'm making nondeductible contributions -- it's just arbitrary money at that point. Does it depend if I paid MA tax that year/lived in MA/filed an MA tax return? Do I basically have to pay tax up to the amount that I've ever contributed out of state? On the other hand, (
https://www.mass.gov/info-details/tax-treatment-of-non-government-pensions-in-massachusetts) refers to "Any taxable parts of rollovers included in federal gross income", and my conversion doesn't seem like it would count as federal gross income. Extra confusingly, Turbotax erroneously claims it is federally taxable when it prompts me to fill the MA form, but doesn't show any income on my federal return.
