This is the problem with DCFC in the wintertime. The cars will restrict the charging rate to protect the batteries, and when you are paying by the minute, you can pay through the nose. The last time I tried a 50kW charger, I started out at 28kW. After about 5 minutes, the charge rate jumped up to the mid 40's. After 15 minutes of that, it dropped back down again. This charger happens to be free, so other than wasting a bit of my time, there was no actual cost to me.