That's very true. When that driver drives an hour, he's already slept eight hours. If he drives an hour and then has to sit here for eight hours and then reload and go, he's burned nine hours of his clock because his clock was running.
Now, on a 16-hour window, he only has nine hours left to drive. He's actually going to be driving tired because he's been sitting around here doing nothing for eight hours when he could have been driving, if he hadn't had to sleep eight hours prior to that.