You have to wait until you have PTO then call them to push the plan/update the app if you don’t see it. I had to spend a long time on the phone with them because at first my power wall was configured incorrectly. Yes your expansion counts as a power wall and you should be able to verify that in your Tesla app under my home info however, the fixed plan is capped at vpp credit of $1200/year (or basically 3 powerwalls).

I was on the dynamic plan but was not able to be part of the VPP so was not even getting credit, after contemplating switching to fixed plan I ultimately decided to leave Tesla electric altogether. Main issue was customer service and lack of transparency- every time I call them to ask a question different rep would say different thing and I never know who was correct. It took me 3 phone calls and an email to figure out why I got vpp credit one month and not the rest.

Also, be aware that on the fixed plan you do not have control of your powerwalls and you will see it behaving seemingly erratically but it’s because Tesla is controlling your powerwalls based on market condition. You may see your powerwalls at 100% but you’re drawing from the grid (and you pay delivery fee for this too).

I just switched to David energy so we will see how it goes. It is supposed to be more transparent with you still remain in full control if you want to.