That's really funny. I've seen several different cars and while the pads never wear totally evenly, they are always within a couple millimeters of each other.99% of my experience is with Volvo, and I don't think I've ever seen one in 10 years with even pad wear. That may be different on another brand, but that's my experience with Volvo. And it's different between models as well. P2's usually wore the front left outer pad and right rear outer pad way faster than the others, sometimes a 3mm difference in pad wear. The P3's tend to wear a bit faster on the right rear inner, and left front inner pad, but sometimes the left rear outer. Go figure.
There is no brake testing here, at least not in my state. I agree with you that the only cause of this uneven wear would be different pressure applied. The car doesn't show any adverse behavior when braking in any conditions. I am left to believe that the right wheel has less weight on top of it so if locks up easier than the left one. the computer reduces pressure in that circuit more often and therefore the pads wear less. It is hard to believe though since in light braking it should not have any pressure control since there is absolutely not lock up or differential slip.I can't see how some brakes would receive more pressure than the others. Brake force is as far as I know electronically distributed today compared to mechanically on older cars. I think a lot older, but still. Not sure how MOT's work in the states but I'm guessing brake force is tested on some kind of roller that should give you kilo-Newton readings on each wheels braking performance. That should tell if it's poorly distributed. Or a simple hard braking, should reveal if the problem's occuring one sided.
^ I think this is the root cause.Brake force is as far as I know electronically distributed today compared to mechanically on older cars.