One has nothing to do with the other.
Ref 1: "Can you tell if the ball went forward?"
Ref 2: "Golly gee, boss, I just don't know."
Ref 1: "Ok, let's go with that ruling."
Ref 2: "Well then, where do we spot the ball?"
Ref 1: "Well, the ball clearly landed at the 21 yard line, therefore, we HAVE to spot the ball behind the 21 since we are claiming it was a forward pass."
Ref 2: "But he was getting tackled and released the ball before he reached the 21."
Ref 1: "Yes, I know, but we can't say we don't know if it was a lateral, and then spot the ball exactly where it landed. That makes us look bad."
Ref 2: "So we just pretend like he released the ball a half yard to a yard behind where he actually threw it?"
Ref 1: "Yes, we do."
Ref 2: "You got it, boss!"
In an obviously tongue-in-cheek interpretation, that's what the behind-the-scenes conversation had to be like when they were deciding where to spot the ball.