Some of it still depends on your energy level and mood, because even when you're sleep deprived you'll have relatively energetic periods.
But in general I'd say consistently missing a few hours here and there is worth 100-200 points. Consistently missing 3 or more hours a sleep every day builds up to 500-600 points. I remember one month I got about 3 hours of sleep every single day. I tried to play chess and it was a bizarre experience. For example I'd specifically look at someone's knight on c5 to see if it could fork me on c7. I'm looking right at it specifically for that reason. I conclude it can't legally move to c7. So on the next move I'm forked by a knight on c7. Really weird stuff like that.
Your thoughts...