That linked documented was sponsored by Sentry, who led the development of FSL. I don't believe it's accurate to call DOSP an "OSI concept" -- meaning, it's not something the OSI invented or coined. OSI also does not consider such licenses to be approved under their open source definition.

As for the timeframe, FSL uses a 2 year period.

edit to add: just to be clear, I'm a fan of FSL and Fair Source licensing, and do not consider lack of OSI endorsement to be a problem.