Yes my car is similar the nav is always 5% soc lower than the actual battery % when you get to your destination. Dealer said they fixed it but still like it currently it has not always been like this though.
My car was in for the last 3 days for a number of range reporting issues. The technician said it was down to me switching from summer tyres to winter ones. I explained they are all season and the range increased ditching the Bridgestones. It has to go in again, hopefully this time to someone who pays attention when reading the job card !
I collected the car and the Sat nav said the battery would be 9% less on arrival after a 4 mile drive. I did explain that a consumption of 2%+/mile is a rate of 1.9kw / mile versus the 3 miles / kw I was getting before the fault.