There is a TT oversight regarding form 8960. TT does not reduce your investment income by state and local taxes when calculating the investment surcharge. You can do it manually and in certain situations, it will reduce the surtax you owe.
To enter the state/local investment taxes on form 8960: You'll have to determine the investment portion of your state taxes then switch to TT "forms" mode (there is no interactive screen for this). Right click on line 9b and select source. This will show you the worksheet that feeds into 8960 and show you the specific line in the worksheet you need to complete.
If you have trouble entering the correct data into the worksheet, you can right click and select override, but an override should not be necessary if you adjust the worksheet.
This method works for TT 2020 download premier. Be aware TT does not provide much guidance about 8960 or an interactive screen to correct the worksheet. I recommend reading the IRS regulations or consulting an expert if you are not familiar with the rules around 8960 and how to determine state/local investment taxes. The IRS suggests using any "reasonable method".
