I agree, I'm pretty sure riding straight through cost me time in the end. The time I did it, I rode with some other people. One of them stopped to take a nap, and about an hour later he passed us and we didn't catch him for a long time. That's about the most miserable I have been on a ride. Just before sunrise seems to be the low point when I'm really tired. I remember sitting at the 500k control, looking at one of my riding companions. He looked like I felt, and it made me laugh. Turns out people don't appreciate that for some reason
Just an hour and a half is all you need, much better to do that than ride straight through. I'm confident that had I slept that much, I would have finished in the same time with fewer sleep-related issues