He seems to back his numbers up with other publications. So I’d say better than “useless”.
Maybe useless was not the correct phrase.
When you are off on each variable in your equation by 10-50%, your result in the end is going to be way off.
His numbers are way off. I know this because I've ran trucks for years and can see the gaps in not only the numbers, but also the logic of someone that doesn't know trucking.