One series isn't our preference but there is just a lot of “variance” dealing with the pros.  Some of them like Casey, Mike Leah, Daryl Jace, etc are great about turning in videos and actively producing.  Some do it once or twice and lose the motivation.  Sometimes behind the scenes stuff happens and we have to part ways.  Most of the time though, they lose interest.  Which is why we're constantly looking for new talent.