Reading up on cut blocking vs. chop blocking and finding out the source of why the block on Cushing would have been legal in the box, I keep getting Rule 12, Section 2, Article 3 & 4 of the NFL rulebook.
Here is the wording:
ILLEGAL BLOCKS BY OFFENSIVE PLAYER
Article 4 An offensive blocker cannot:
(b) charge or fall into the back of an opponent above the waist, or use his hands or arms to push an opponent from behind in a manner that affects his movement, except in close-line play
Bold added, but I believe this is the part of the rulebook that they might change, IMO.
It says "above the waist", so I'm a little confused if this is exactly what they are talking about updating.
edit: further reading, and I have always thought it was illegal no matter where it happens like 'cak mentioned, it specifically mentions "A player of either team may block (obstruct or impede) an opponent at any time, provided that the act is not: (j) an illegal cut block;" (Rule 12, Section 1, Article 1).
So I think the article is just wrong in confusing cut vs. chop blocking, and the questions to our GM and HC have been misconstrued to fit the article's agenda. JMO