For my sorority, the required GPA is actually lower than what the local NPC sets. THerefore, we go by the highest. I think that's pretty much standard; you take the two and go by the higher one.
And i'm sure that fraternities go lower than sororities; my boyfriend joined a fraternity with a 1.7. Granted, it was local so they weren't bound by the requirements many national GLO's are, but still.