-"Offensive pass interference rules apply from the time the ball is snapped until the ball is touched."
-"Defensive pass interference rules apply from the time the ball is thrown until the ball is touched."

-"Actions that constitute defensive pass interference [after ball is thrown] include"
(e) "Cutting off the path of the receiver by making contact with him without playing the ball."

-"Actions that do not constitute defensive pass interference [after ball is thrown] include"
(a) Incidental contact by a defender's hands, arms, or body with both players are competition for the ball, or neither player is looking for the ball. If there is any question whether the contact is incidental, the ruling shall be no interference."
(e) "Contact by a defender who has gained position on a receiver in an attempt to catch the ball"

-"Actions that constitute offensive pass interference [after ball is snapped] include"
(b) "initiating contact with a defender by shoving or pushing off thus creating separation in an attempt to catch a pass."
(c) "Driving through a defender who has established a position on the field."

HCFF Comments
What is "established a position on the field"?
Rule (e) and (c) can be seen as contradictory: "cutting of the path of the receiver" and "driving through a defender".