I tend to agree. Adjusting my new pedals from the factory setting (too lose) to about the mid point greatly increased the stability of my foot, which I think may have reduced my knee issue.
If you just want to try a pedal with more float, a cheaper solution to try might be using Look pedals. They have 50% more float than Shimano pedals.
If you use Shimano, remember there are 3 cleat types with regards to float. Blue, red and yellow.
I prefer yellow. If anyone wants to try blue I have.a new pair gathering dust...
Andy