I believe it was in this forum somewhere that a quote from Jaguar that said the maximum charge our cars would take, with the right chargers, was 107 kW/hr rate for the 1st few minutes of charging, when the battery is near it's 0 miles left. This is slower than Ford's Mach E quoted 150kW/hr charging. But, it does appear you can calculate that the Jag will do slightly better miles per 10 minutes than Ford is quoting, despite the slower charging rate. I do agree that miles per kW is a big guessing game. Who knows what the Jag's low kW cutout is on the lower end? Jag has claimed ~84kW is 100% charged. I am sure there is a limit that also prevents us from using all that 84kW on the low end too, assuming 84kW is not accounting for that lower limit loss of kW.
My Ford Focus Electric had a published 23kW battery in it. A scangauge read the actual battery kW when 100% charged was 16kW(it took 18.2kW on my wall charging meter, to fully charge it, after the battery empty message came on. Heat losses should explain the 2.2 kW charging loss) . Supposedly, some of that lost 7 kW was on the bottom end limit of the battery.