I got my pre-MVPA and found that there was a charge for RTA tax even though we are just outside of the Sound Transit tax area.
Tesla removed the tax after I pointed it out to them.
If you are not sure whether you are located within the RTA tax area and you are taking delivery at the location where your car will be registered, you can use this map and type in your address for verification:
Sound Transit Map Explorer
You can find general information about the tax on this page:
Our taxing district - SoundTransit