The ICE version probably loses 1/4 of its MPG under load also, maybe more. I always thought the "hurr durr, you can't tow with an electric truck because you lose range" argument was misplaced.
Too bad they didn't think to simultaneously test an ICE F150 in the same manor. I'm guessing there wouldn't be much difference in range reduction percentage, overall. The biggest issue with the BEV is, you have less range to begin with, so it becomes an issue a little quicker.
An old van I had with a big block(power to spare) got 9-10 mpg regularly, I never complained, it spun tires and got up to speed fast. But one time I loaded it pretty dang heavy with about 3000lbs of cargo mpg on a long trip went down to 7-8. Even with 38 gallons of fuel. I wasnt getting much over 200 miles before stopping for gas. Before I always made it 300 miles. Electricity is no different. Speed of juicing up is the only factor here. What I want to know is how is battery lifespan affected if you drove, then fast charged, drove, fast charged, etc on a roadtrip switching drivers and running straight through.