The indicated range on any EV is only ever an estimate but with most it is an educated estimate in that it adjusts the indicated range based on how the car was driven over the recent past. Many of us call it a "guestimate" and the range indicator we often call the "Guess'o'Meter" or GoM Drive the car hard then not only will you get less actual range but from then on the car will assume that it will be driven hard and the estimate will be lower. Drive the car gently for a period and the car assumes more gentle driving for the future and so the estimate will go up.Ah, interesting; that explains a lot. I went to Brighton yesterday which for me was about 85 miles. If I couldn't get a charging point I planned a 20 min top-up at Cobham Services on the M25. As 90% of my journey was on the motorway, and they were clear, I spent the majority of that time at 70 mph. The 85-mile journey took nearly 140 miles off the 'range'. In the time I was there, I charged the car back to 85%. On the journey back I stayed at 60 mph and this time the 85-mile journey consumed approximately 105 miles of 'range'.
Also... the faster you drive the less range you will get so you seeing a drop in indicated range reduction when you drove slower is to be expected.