We selected a Green Mountain free nights plan when we put solar and powerwalls last year. Its worked out very well. We have a 16kW system with 4 Powerwalls.
Our plan last year was for 12 months, and I just renewed it for 2 years. Our renewal was for the similar plan - "Pollution Free All Nighter 24" -- without the premier. The EFL was dated on 4/6/22 and has a daytime energy charge of 22.407 cents -- otherwise the numbers are the same as you show. I'm not sure what the difference is for the "premium" plan, but you might want to see if you can find the "regular" version to see if it has a price difference. That's a big daytime rate jump in just 30 days -- it might make sense to look at a 1 year plan and take a gamble that energy prices drop a little bit by next April (you can renew with GM about 60 days in advance, so look at plans starting then).
FWIW, our original plan had a daytime charge of ~15 cents (the combined REP+TDU rate is just under 19 cents/kWh). Our new plan has a combined rate of ~26.3 cents. I modeled our usage since last Sept using the new rates, and since 98% of our grid draw is at night (ie free period), it looks like out bill will increase by <$1 month...
Since we received PTO on Sept 1 last year (install was late June, PTO took over 2 months...), our electric bills have been in the $5-8 range, with one bill that was ~$14. That "high" bill looked like a billing issue -- Green Mountain showed we had grid draw one day that the meter data did not reflect. I didn't complain since I really don't want to draw any attention to how we use the plan.
I do have the plan set in the Tesla app and its set to run on cost savings mode. For the plan, I set Peak as 6a to 8p to match the plan. I then put in the combined CenterPoint and Daytime Energy charges, rounded up to the nearest cent (Tesla doesn't allow decimals to be entered) -- for the rate plan above, that would be 31.8005 + 3.9416 cents -- so would enter 36 cents in the app. For the sell and off-peak rates, I entered $0 and the app blanked them out. The system draws from the grid from 8pm to 6am, switches to draw from the Powerwalls at 6am, then charges them back from solar, only sending excess to the grid once the powerwalls are 100%. We get a little drain in the evening -- typically ending the day with the PW anywhere between 85-95% (cloudier winter days were lower, yesterday was nice and sunny, with sunset after 8pm, so it ended around 94%.
We generally only charge the cars (we have a 3 and a Y...) at night. Occasionally we'll charge during the day, but that rarely results in any grid draw.
