CBCinCA,
The answer is that you do not override TurboTax in this situation. The reason is that in order to receive the additional deduction, CA requires a copy of the federal Schedule A, whether or not one is used for the federal return, and entries on the 540 Schedule CA are added or subtracted from those on the relevant federal forms. I was in this situation in 2018 with an additional property tax deduction above the $10K state and local tax limit that had caused me to use the federal standard deduction for the first time in decades.
