[MD Longhorn]

Tell me then which part I am misinterpreting:

8-4-1: It is a safety when the ball becomes dead out of bounds behind a goal line ... and the defending team is responsible for the ball being there.

8-6-1: It is a touchback when the ball becomes dead out of bounds behind a goal line, ... and the attacking team is responsible for the ball being there.

8-7-1: The team responsible for the ball being out of bounds behind a goal line ... is the team whose player carries the ball or imparts an impetus to it that forces it on, above or across the goal line.

8-7-2a: The impetus imparted by a player who ... fumbles the ball shall be considered responsible for the ball's progress in any direction EVEN THOUGH IT'S COURSE IS DEFLECTED OR REVERSED AFTER STRIKING THE GROUND OR AFTER TOUCHING A PLAYER OF EITHER TEAM.

And the reason I felt the 1st case was a safety, but the second a touchback is because of:

8-7-2b: Initial impetus is considered expended ... if the ball comes to rest and he (a new player) gives it new impetus by any contact with it.

The rules seem to be calling out that if the ball comes to rest, and is then hit - that new hit is considered new impetus. Why would the rule state that specifically, if the intent was for ANY hitting of the ball to be considered new impetus. If the ruling was supposed to be as you describe, 8-7-2b would have not said "if the ball comes to rest".

I would defer to your more experienced judgement, but from just the verbiage of the rules, it seems that case 2 should be a touchback. I don't know how one would adequately define "The fumble rolled to B-5 and will not be able to roll into the endzone but is still rolling." How do you know a ball will not be able to roll into the endzone unless it comes to a complete stop? A ball has a funny shape, and fields are not level.