Well from the abstracts and info that I posted, it does vary with sleep and waking.  if as it says in one cortisol can climb up to 50% within 30 mins of waking, then ACTH will preced that really.  That is because ACTH is the first thing that rises before cortisol.  It says in that study that irregardless of waking time, or what time you go to sleep, or how long you have been asleep for, that when you actually wake, your cortisol rises by 50%.

You have to also think about things in a logical sense.  When we wake too early, we get tirder sooner.  More often than not we want to hit the sack earlier.  That has shifted the time you go to sleep and therefore in my opinion means you will reach deep sleep earlier--two hours later release GH--and you are bound to be getting to the the point where cortisol first starts to rise a lot earlier too.  On the other hand if you have a late night, notice how you want to sleep in?  You feel really tired all day if you have to go and work and get up early and consequently I used to fall to sleep at my VDU and could not keep my eyes open.  I used to work Sats and Sundays on a mail ordering call center.  I would sometimes go out with the girls for a drink and club it and not get back until 3am.  Fall asleep--but have to wake for work at 7am and go to work and go and be there all day.   All I did was nodd all day and feel tired and as soon as I got home I would want to get my dinner and hit the sack!   Going to sleep earlier actually alters when you wake up.  I have done this since bruce left.  I started to go to bed when the kids go because I am not interested in staying up---and I wake a lot earlier.   So I do not believe that these things all stay on track when you do that.  I feel it shifts things instantly not just over time.  

However,  you would not want to change your meds around the occasional night out.  If you were shifting those things on a permanent basis though, or your rythyms were different to the sleep waking on the current regime of 7am, 12:00noon, 5.30pm and 3am, you would want to look at that for sure.