No, that's about right.As someone who cannot us rapids anyway, I am slightly nervous about the notion that a public rapid charger which may not be too well maintained would be in control of what happens to my battery. I thought that all the tapering of charge rates and power levels was controlled by the car to protect the battery. Is that wrong?
When using the OBC with AC the conversion and charging is fully controlled by the OBC. However the charge point or granny charger communicates with the OBC to ensure the cable is properly connected and to tell the OBC what the maximum current is that it can pull - obviously drawing 30A from a 13A or 16A supply will not end well.
With a rapid DC charger the external unit does the AC-DC conversion and has the power electronics to regulate the DC output to the car. But as with the AC case the car and charger talk to each other and it is the car that tells the charger what power it can accept. So a 150kW charger will only put 50 max into a 50kW capable car. As the car battery gets full, or is cold, etc, the car will tell the charger to push less current.
So yes, the car is in control, unless the DC charger goes mad. In that case I imagine the car's BMS will take evasive action, perhaps opening the main contactor.