time of day when ebooks are actually released for amazon kindle, B&N, etc

[grr]

So I know this may be ridiculously obsessive of me, but there's been many a time when I've put a B&N or Amazon kindle ebook on preorder, and desperately checked -- late into the night/early into the morning of said pre-order date to see if that book had become downloadable yet.

So, for instance, ebook X may be officially marked for release for "today" -- may 25th (at least in my time zone), but not literally at 12:00:01AM (at least in my time zone (EST)).

I've not rigorously logged my results (nor gotten an official answer from amazon or bn customer service), but in the past, I've found that certain kindle books are definitely available by 5AM EST, and unavailable at say, oh -- I don't know -- 1:26AM EST?

My guess is that there's some "official" server clock cutoff (just like ebay USA times are marked to PST), so maybe at 3:00:01AM (EST) = 12:00:01AM (PST) -- kindle books unlock?

I have noted (but again, forgetting to rigorously document my experience) that in at least one instance:
1.B&N and Amazon had the same release date for an ebook
2.Amazon and B&N did not have it available yet at 12:59AM (EST)
3.Within a few hours or less, Amazon was still in pre-order mode, but B&N was in order mode.

Any empirical observations, or actual knowledge of policy, from fellow obsessives / night owls out there?

[and yes, I'm aware of another way to get books even earlier -- eg, ebay and the market for Advanced Reader Copies (ARC's) and proofs, but I'm always a little uncomfortable w/the ethics of buying them -- that being said, I'll occasionally succumb and go for it]

[ATimson]

I know that two titles releasing today from Random House showed up on Sony's store somewhere between 10 PM and midnight EDT last night. (Which makes me think it's probably supposed to be midnight *EST*, but they forgot to take daylight savings into account.)

Fictionwise preorders used to unlock somewhere between 1 AM ET and 8 AM ET, but they haven't been doing those for a while. (Still don't see today's RH titles I want... hopefully they'll be up by the end of the week, 'cause I'd like to use some of my Micropay that's burning a hole in my account. If not, I'll go elsewhere.)

[VictoriaP]

I've previously always had Amazon preorders show up in the first 10 minutes after midnight, PST. Last night, however, I was waiting on orders from both Barnes & Noble (Penguin) and Amazon (Random House). Both books released sometime between 12:30 and 1 AM.

[ladyofmyown]

Hello! I read your posts last night while awaiting arrival on an ebook I preordered from Amazon. I received the email from Amazon telling me my book was available for download at 2:05 am Central Standard time. The email also contained an order summary, meaning they didn't charge my Amazon account until the book was downloadable. This particular book was published by Simon and Schuster. Not sure if the publisher decides when it is released or Amazon themselves. I hope this helps! ;-)

[user_none]

My guess is it has something to do with the time zone their respective corporate office is located in.

[rcuadro]

I just look for it when I wake up. I dont know why I pre-order ebooks since it is not like they are going to run out of them... but alas I do