There's a point where percent charge at home on EV tariff vs percent charge at public chargers. If you go over that point, you are better off buying dino-juice.
Always got to remember, for most people, rapid charging is rare. I used to do it once in a blue moon in Leaf, I don't foresee needing it for our normal day-out in the Tesla, only during actual road trips. So I personally don't care about rapid charging prices, I only care about the service associated with it: many stalls per loc, toilet, restaurant, etc.
Also got to remember, destination charging is usually much cheaper or sometimes free if you can get on them.
ABC = always be charging.