I'm an unapologetic night owl. I don't wake up before 10AM if I can help it, and I get a lot of productivity out of late night hours, both for work as well as personal endeavors. I enjoy my groove and would not change it. Were an employer to require me to be in the office early, I would refuse the offer or seek new employment. Given the nature of software work, I don't think this is at all unreasonable. As long as the team is able to rendezvous mid-day for several hours, it seems petty to hold individual actors to a universal schedule.