Not true. First car to connect gets priority, it gets whatever it can take. The subsequent cars to connect will get what's left. If the first car plugs out and in for just a second or two, it'll drop in priority.
Thank you. You're right.
Understand that every car that charges starts out at a high rate of charge, and then almost immediately starts tapering off to protect the battery pack. Nobody charges at full rate more than a few minutes. Nobody. And unless you can see their screen, you have no way of telling.
A car may pull in to charge, with a hundred miles still in the pack. The charger ramps up to the rate that is safe for that battery. If the car has only 25 miles on the pack, the batteries can take a higher rate of charge for a few minutes. If the battery is hot, the charge rate is reduced while the fans cool the pack.
What this says is that hardly any car will start with getting full charge (lets say 120 kW), and then it gets highest charge ONLY for a few minutes. The charger quickly starts to ramp down. You can see this on your charge screen by watching how many miles per hour of charge you are getting, and it drops minute by minute.
What this also means is that, into the charging cycle a few minutes, the charger is not putting out full power, and a second car can plug in to charge with what's left of the 120 kW.
The problem is, you can not know what the first car is getting. If they have been of the charger for 30 min, the second car will get almost full charge, almost as fast as if car #1 was not there. If, on the other hand, car #1 just pulled in with 10 miles of charge left, car #2 will get a smaller amount, which also depends on the charge of car #2.
So. Try to pick a stall that is not sharing. if you must share, and have a choice, pull into the spot beside the car where the lady is reading her book: She's probably been waiting, and her car is ramping down, and she will leave. Better yet, get out your own book.