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2 different supercharger experiences day apart

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05/05-good charging session. I supercharged @Pickering,Ont. from 30-61% battery without problems. Initial charge rate (after ~2min ramp up) 110kw slowly dropped to 98kw at 61%, Cooling had kicked in around 45%.
06/05-a day later supercharged Lawrence Ave, Toronto,Ont. First point others were not having problems and I was NOT paired up to another charging car at any of the 3 spots that I tried. Started at 34% battery only charging at 44kw. Moved car after 5min to spot just vacated (that driver reported had charged at usual high rates). At this second spot only charged at 36kw. After waiting another ~5min I moved my S90D to a third spot. There I was able to charge at 72kw. Better than either of the first 2 but not the 100+ that I was getting <24hrs earlier. Cooling kicked in around 50%. Another 90D (ironically in the same colour) pulled up to the first spot I had vacated and he was charging at 100kw+ in <2minutes.
So... I doubt that something suddenly happened to my battery. Car has been driving great. Temperature mild (in the mid teens) both days. There was no restriction on regenerative braking when I started driving either morning nor at any point during either day. At Pickering I had just come off a 1.25hr drive on the highway at 100kmh+. On the second day I had driven 20min on the highway then parked for 2hrs then driven10min. Is it possible that my battery was simply not at optimum temperature to supercharge quickly? Is there another reason I should know about? Comments/suggestions please.
 
Is there another reason I should know about? Comments/suggestions please.
Yep, I have a pretty strong theory of what causes this, as I've seen it reported before. On the bottom front of the car there are those vent areas that have the small radiators behind them to blow air through to do some active cooling. Well, for aerodynamics, they have some flaps that close over those (frequently called louvers), when that cooling is not being used. Sometimes one of those louver controls or motors malfunctions and can't open up, and that side stays blocked. That is a big restriction on cooling when the car is trying to Supercharge, so the heat level stays high in the battery, and the car has to hold the Supercharging speed down to keep the heat level un-damaging. Here's a thread that mentions it, where the service center can run a thermal test.
Failed Thermal Test | Tesla