As I write, the time and date on my machine is 2013-11-14 09:40. When I type "now" into the start point field, it parses it as (2013-11-15 09:40).
I'm not really sure why this happens. I get the same results on Mueller's page for his Date plugin, so it's probably an issue with the date parser itself.
Could you implement a simpler date picker that works better?