Apparently with V3 supercharging the battery is heated to 50C using 9kW but of course that doesn't last very long. They previously only billed for energy added to the battery. Maybe the battery itself generates a substantial amount of heat while being charged quickly?
Seems like they should have just raised prices again, while more accurate this seems like it will just make people upset and lead to endless questions like "Why was I charged for 60kWh when I only added 50kWh of charge???".