Instead of a 90-degree offset, stacking the blades on top of each other will allow them to make two cuts in any grass blade, pine straw, etc. that's sticking up. This will make the cut material two smaller pieces vs. one large piece, which means it will disperse move evenly or fill a grass bag more completely.
All but a couple of Honda models use twin-blades this way, and the cut quality is excellent.
Caveat: I work for Honda, but the preceding is my opinion alone.