Not the same at all....
Section A/
If "the aircraft has dispatched with one or more reverser(s) inoperative", and THEN suffers ANY in-flight failure, it is immediately presumed that ALL of the reversers are now inoperative.
--> Simplistic? Yes, but it is safe/conservative.
Section B/
Presumes normal dispatch, and an in-flight failure(s) occurs that leaves at one reverser available, then credit can be taken for the use of full reverse on that one reverser.
Mind you, it only factors in one reverser, which ignores the value/possibility of having more than one (A340 - up to 3) available.
All told, this presentation is better than Airbus' last attempt, where they ignored the possibility of a reverser inop at dispatch altogether.