I just made a 1,500 mile road trip. I stopped at a total of 9 supercharging stations. I noticed the same thing you mentioned. I’m also curious as to why this happens, bit I wonder if the battery isn’t always in need of preconditioning en route to your supercharger, regardless of how it was input in your navigation. So I should’ve paid attention to the times my battery would be “warm” from driving 200 miles straight on the highway on my way to the next supercharging station.
My Model 3LR has the acceleration boost and after leaving a supercharger, the car is wicked-fast since the battery is at it‘s peak state of readiness/condition in.