IIRC, every angle I saw didn't really show the play from behind him, or rather from closer to the middle of the field. Like, there's an angle showing the knee coming up but it obscures the defender making contact with the ball. It seems the book is basically saying there can't be any doubt ever for them to even consider overturning plays. Like the refs are supposed to act like they have a memory of a goldfish and no assumptions can be made at all
The other part of this is you can't tell me the the following snap didn't go off before there was an official's timeout. Like, it doesn't matter if the call came from the league office in NY, an entire play was almost ran before they blew it dead... lol