The Robot Coupe is widely regarded as the standard food processor for professional use. Neither it, nor the industry-leading Cuisinart or KitchenAid food processors have those middle blades. As such, it seems unlikely that they are requirements for a quality unit.
The maximum rating is based without the top blades inserted into the pitcher. This drives the greatest power.
TIP: When pureeing, use only the bottom blades for best results.
Top [middle] blades are needed to power through tough ingredients like ice, solid fruits and vegetables.
For the ...
I use salt and STTP when I make burgers and bakso, (that’s the hard meatballs).
Sodium Tripolyphosphate (STPP)
There is an article on it that may be of interest.