My testing of the What-If Worksheet in 2016 TurboTax shows it to be working correctly with regard to using 10% of AGI for 2017 for those age 65 or older in 2017. Make sure that you have the latest updates to 2016 TurboTax and that you have marked the box to use 2017 tax rates for the particular column you are using for the 2017 estimate.
