You are right.
I know that when I want to drive a long range I avoid to see more than one of the three Power Bars in the display. With one bar visible, I can't drive faster than 55-65 km/h. With that style I drove more than 240 km in one day. Of course more charging than driving.
I found an interesting overview incorporating speed, range, time used for netto 100km distance, charging time for 100 km, time used bruto for 100 km, average speed for 100 km. Also for 200km.
It discloses that when driving a speed of 60 km/h is optimal. When driving longer distances drive more slowly.
Just translate the German texts.