What does "controlling" mean, in the sentence
'The Mile/kWh value in red below is controlling, NOT speed'
Controlling means that should you be driving 50 mph with a heater blasting, you could be consuming energy at a rate of 2.5 miles per kilowatt hour.
In the past, people have tried to equate average speed and other methods with range, but the only thing that actually matters is how much energy is stored in the battery and what is the consumption rate.
So, 2.5 miles per kWh * 20kWh stored = 50 miles range, assuming your consumption doesn't change. It doesn't matter what speed you ultimately derived those miles per kilowatt at.
But, given the parameters of a level dry road with no significant wind on a nice warm day, then yes, the speed well very closely align with the published consumption rate.
65mph will only indicate 3.9 miles per kWh in those circumstances.