Partly out of interest and partly out of the desire to stir things up
, couldn't "appropriate" pressures depend on the tire manufacturer (based on proprietary compounds, designs, changes in technology since 1980 in my case, etc.)?
For example, the Pirelli on my previously never-on-the-pavement spare tire recommends 36 PSI while the Mastercrafts that the PO put on recommend 44 PSI (Max). If the Mercedes engineers base their pressure recommendations on the tires that came on the vehicle as standard equipment (I'm assuming the Pirelli's were), couldn't that change if tires from another manufacturer (Mastercrafts) are installed? I'm guessing that the tire manufacturers' pressures are based on some engineers' recommendations.
Is it the Mercedes recommended PSI no matter what or do we assume the tire guys know something about how their tires perform and wear based on their numbers? As a seed and fertilizer guy (meaning I know jack squat about tires and PSI), I would guess the latter. I've always run with the pressures set in the range on the tires and have always gotten even wear and about the expected longevity.