My MMM manual does show a blade orientation, so I was trying to figure out the logic begind it all. The only thing I could come up with (and ignoring any belt slippage) was that the blade on the left (from operators position) was slightly ahead of rotation than the middle blade, and the middle blade was slightly a head of the right hand side blade. The theory being that the grass is handed off from left to right for better discharge. Don't get me wrong, I don't put a lot of merit on this all, but that's the only logic I could come up with according to their diagrams.