I just spend 40 minutes on the phone with Turbo Tax with the same problem. After all of that time they said the following: 1) if your retirement was higher than the public pension" then MO tax is paid. (I do not know what this means nor did I receive any other retirement income, nor should that even be relevant as I do not receive SS either); and 2) you will need to pay for a tax expert if you want additional help.
