This for me is the crux of it. You're not creating more time, you're moving your waking time to allow you to make better use of it based on fewer interruptions

This for me is the crux of it. You're not creating more time, you're moving your waking time to allow you to make better use of it based on fewer interruptions or whatever. Early morning has fewer distractions than evening (nothing on TV, you can't phone people, e-mail isn't arriving, forums are quiet and so on) which is why it can be productive time for solo work, but you can't sustainably just take that time out of sleep without something (usually one or more of attention span, short term memory, general mood) giving out.