NCAA DPI: 1 yard rule

[Texas Aggie]

Had a play tonight: (7th grade) receiver fires off the line and gets blocked by the defender 2-3 yards or so downfield. Pass is thrown to that area and I flag DPI. Coach is screaming that receiver initiated the block, which I didn't really agree with. It looked more like they were both blocking, but the receiver could have been defending himself.

Anyway, what I think the coach was really arguing without knowing it was the one yard rule that allows a defender to block within 1 yard of the LOS. 2 Questions:

1. Is the "1 yard" more like a "1 second" (related to offense set prior to the snap) in terms of distance -- in other words really one step? Should this be enforced liberally or conservatively (i.e. if this is, say, a yard and an inch downfield -- flag or no; which team is the one that has to gain an advantage)?

2. Our mechanics call for us as wings to "release" 5-7 yards downfield when we read pass. Even if I'm on my way to that area, I may have lost exact focus on where the LOS is. Related to Question 1, how do I judge this in a real live play?