How did you figure that out? And having a phase advance should just mean that you could shift your bedtime and waking time forward but still get a similar amount of sleep compared to someone with a "neutral" phase, whatever that means.
As for the phase shift, I've always had what I thought was maintenance insomnia but at some point I realized I always waking at exactly 4:30am. Going to bed early resolves the maintenance insomnia (also travelling eastward more than a few hours or so). My father and brother are the same.
I'd love to get a DLMO done to confirm. Thinking about experimenting with tracking core body temperature monitoring soon.
FWIW a 24h ambulatory blood pressure study actually showed a phase advanced nocturnal dip.