Interesting concept. I think I am pretty typical and here in late April, I have supercharged 5 days so far, a total of 9 charging events, not counting destination chargers.

I would suggest that the rates in the paid tiers should be on a “per minute” basis rather than based on power delivered. Why? Because superchargers are much more efficient up to 70%, and start being less so, becoming slower and slower as the battery gets topped off. People should be encouraged to continue their trip with the minimum charge possible (plus a reasonable buffer — approx 15% SOC).