Charging speed is not a single number, it is a curve that falls as the battery fills. A car rated at 150 kW might touch that figure for four minutes near 25% state of charge and spend the rest of the session well below it.
This is chemistry, not marketing. As lithium ions pack into the anode, the cell's ability to accept current safely drops. Push harder and you trade a few saved minutes for measurably shorter battery life. Every sensible vehicle manufacturer tapers deliberately.
Temperature is the other variable. A cold pack in January will refuse fast charging until it has warmed itself, which is why a car that preconditions on the way to a charger routinely beats an identical car that did not.
The practical takeaway: plan around 20% to 80%. The last twenty percent typically costs as long as the first sixty, and on a road trip you are almost always better off driving on and stopping again.