I don’t think that I would ever think the 4th down fumble rule did not apply. This is just a got cha’ play. So what you are saying is that anytime A recovers the ball with Any part of his body out of bounds the 4th down fumble rule does not apply (but if between the goal lines the forward fumble OOB would apply) I am just trying to understand.
Yes. The '4th Down/Try fumble' rule only applies if the ball is
caught or recovered by a player of Team A other than the fumbler, and the ball can only be caught or recovered if the catch/recovery is completed inbounds. When the ball is dead because it goes OB, or touches something OB, then the 'forward fumble OB' rule applies (all downs), unless the ball is dead behind a goal line. If dead behind a goal line, then you have either a touchback or a safety, depending on impetus.
Both rules are intended to discourage attempts to 'deliberately' fumble the ball forward to gain advantage. The risk/reward for a BC to fumble the ball forward in the field of play or end zone on any down other than 4th is simply too great to justify a rule on those downs. But, on 4th down, especially late in a game, the BC may be desperate, and willing to try to fumble it forward to a teammate beyond him. This was prompted by an NFL situation many years ago when Ken Stabler fumbled the ball forward (deliberately? we may never know) into the end zone where Dave Casper recovered for a game winning TD as time ran out. I'm not sure the NCAA ever had a similar incident, but they certainly saw the potential, and followed the NFL's suit by developing a rule to prevent this potentially unfair advantage.
The forward fumble OB rule is similar. Before this rule, a BC could 'fumble' the ball forward out of bounds to gain additional yardage, as well as get the game clock stopped. This rule put a stop to that. And, if the ball goes OB at the sideline in the end zone or end line, then the fumbling team isn't allowed the benefit of this rule (which would allow them to retain the ball at the spot of the fumble) - touchback.