I imported the data from my financial institution. When I did that, Turbo Tax pre-completed most fields but then asked me about this box 1b and the only permitted replies were those using the drop down menu. Therefore, I ended up deleting all the data that was imported and re-entering it using the dialog boxes which allowed me to enter info as described by Abraham T.
The bug in Turbo Tax appears when a user imports their data from their financial institution.
