bluntforce - 7:27 am on Dec 15, 2012 (gmt 0)
The reason I zeroed in on mobile is that some members in this discussion pulled that difference out of their log files
Not to nit-pick, but I believe that difference was from a script, not log files. I'm a big believer in log files, it's what allows a deeper understanding of individual users and overall user interaction.
It's also why I don't have a lot of trust in user agents.