Pass interference vs Defensive holding?

[ChuckElias]

I'm a resident on the basketball side of this board. I know some of my hoop brethren also officiate football, but I decided to bring this question over here.

I attended the UMass/Maine football game this past weekend. It was a great game and I thought the officiating was excellent (I'm not just sucking up to you guys, either ). But I had a question on a pass play that I'd just like some clarification on. Obviously, this pertains to NCAA rules.

On this pass play the UMass wide receiver ran his pattern and was definitely beyond 5 yards from the line of scrimmage (I don't even know if that matters or not). While the ball was clearly in the air from the QB, the Maine defender pulled on the receiver's jersey. The pass was incomplete.

The official threw a flag and the penalty was called as defensive holding. I thought that if the ball was already in the air, that this would be considered pass interference.

Can someone explain the difference in this case between the two calls? And also is the difference in enforcement only a matter of 5 yards? (10 yards and 1st down for PI, only 5 yards and 1st down for holding?) Thanks,

Chuck