No, no. If you always go to sleep at 10pm, and it gets dark at 5pm, then that's 5 hours of electricity use. But if it gets dark at 6pm, that's only 4 hours of electricity use.

So the idea, I think, was to "take" daylight from before the time most people gets up, when it's going to waste, and put it when folks will use it. Hence the savings.

I'm sure there must be somewhere on the web that talks about it. At any rate, whatever the rationale, my bet is that it was invented during the energy crisis.