Standard business practice in the mainframe world. Amdahl, among others, had a switch. If you wanted to go fast for some period of time (monthly reports?), you clicked the switch and the speed, and rent, went up. When you didn't want to pay for the speed, you turned it off. IBM had similar schemes.
I don't know that the additional mileage was all that helpful. Range anxiety is one of the limiting factors in battery car adoption. On its best day, my Chevy Bolt might go a little less than 200 miles while my Chevy Silverado will probably go 400 miles and there are gas stations all over the place and refueling only take a few minutes.
Still, I really like the Bolt!