"I have worked with proseries for 10 years and to my knowledge they have never done this before."
They have always done this. If there is an update after the return was filed, the system will use the most recent update to calculate the tax. Most of the time updates don't affect the tax, but backing off $10,200 of income at a time will definitely create a change in tax.
Pot Stirrer Gold Medalist - Rio de Janeiro Games