Hi Bluey,
interesting question.
Without being able to directly answer your question on whether the binding settings can be set to a lower level when skiing PMTS, I can definitely say that for me, the stress levels on my knees have been vastly reduced since I started skiing using PMTS. Ever since being a teenager, I've had trouble with my knees (Schlatter - see
http://orthoinfo.aaos.org/fact/thr_report.cfm?Thread_ID=145&topcategory=Knee )
Before starting to use PMTS for my skiing, after a few days on the slopes, my knees were aching a lot. Sometimes so bad that I had to put an ice bag on the knees over lunch in order to keep skiing.
Now when using PMTS, I rarely notice any problems with my knees, despite that I'm skiing much mcuh "harder" now than I used to - until last season, my skiing was mostly a "socializing event" with my kids, while now I'm really getting a good workout each skiing day.
I doubt the "general condition" of my knees has changed much over the past years, so my guess for the reason for not having pain anymore is that PMTS is much friendlier to the knees than my old homegrown technique (outside ski steering etc)
The only time recently when I've noticed knee problems was when a father with a small kid having huge problems on a black run approached me, asking me to literally carry his son down the slope: to do that, I wedged down the slope, carrying the kid. Immediately after this run, I had a lot of pain in my knees for a few days.
Cheers,
Tommy