Rick,
Just came to those numbers by:
1) 0515 report, 0500 at the airport (to allow for the dreaded car park bus), 0415 leave home, 0330 alarm clock; and
2) Many guys I fly with, when discussing the age old topic of "what time did you get to sleep last night" reply with 2300.
I find 2100 about right - sometimes it stretches out to 2145.
Wouldn't it be nice to sort all these problems in one fell swoop!