there are no rules differences in NAIA
the NAIA does seem very budget conscience when it comes to post-season vs. NCAA (and I don't blame them). my one NAIA post season assingment...we drove around 400 miles one way. our game check was $5 less per man than we make in the regular season...we got no meal allowance, had to share hotel rooms...and only one guy got paid mileage (even though we took 2 cars). compare this to NCAA DIII post-season...which has a higher per game fee, everyone that drives gets mileage, you get a per-diem for meals...and you each get your own room.
i am not complaining, a post season assignment is a post season assignment...but you can see that the NAIA does opperate on a smaller budget, and this could explain why for the schools that are in maybe the Midwest or Northeast that don't have a lot of NAIA schools anymore might end up using an crew that works mostly NCAA games