For undergrad D3, 12 hrs is a requirement(at least at DD's school) to be a full time student in order to be able to play. DD had 2 teammates that were taking 12 hours in the fall, each failed a class thus bringing them down to 9 hrs. They could not play in the spring season due to not being a full time student. The coach now requires min 15 hours per semester and certain number of hours of study hall in the locker room.The NCAA is being very generous with waivers. The 12 hour requirement you mention appears to not be an issue at the D3 level.