Doesn't really make a blind bit of difference. It the kids are tired at school, it means they aren't getting to bed early enough.
Although really, the entire structure of sleep and wake is probably not what we're designed for. Virtually no animals have a sort of strict on-off system of wake and sleep as modern humans do, and there's no reason to think our ancestors had such a division either. I think it's very likely as hunter-gathers our ancestors slept during some of the day and were awake some of the night. There's evidence that's what many of us were doing in the medieval era, too.
There simply wasn't the sort of regularity we have now. I doubt the hour here or there from setting clocks forward or back is substantially different from natural variability in sleep from populations that didn't have clocks. Although going back to the notion of us staying up too late, back in the day there was fuck all to do when it got dark: no social media, no TV, no books, nor even significant light to do anything worth a damn except talk and have sex. Most jobs didn't need to be done at particular times. And our pre-industrial ancestors probably worked less than modern full time workers do, as well (at least across the course of a year).
