I don't think the clutches on drills are real precise or meant to be precise enough to "apply" torque. They are very simple slip clutches, mainly meant to "release". The ones I have taken apart have no means of adjustment for calibration (i.e., if you wanted to tune them into a spec). I know torque wrenches and torque limiters have very precise mechanical adjustments, but the slip clutches I have looked at in drills have all been very basic.
It would be interesting to see how repeatable a drill's slip clutch was, if one had a means to test that. I know when I used to use a drill to drive screws, I found that a single setting would never suffice for very long. Small variations in wood hardness, friction, etc, would make almost every screw behave different. So the clutch helps, but is not perfect.
Interestingly, the one clutch that has always worked perfect for me is my 1980s-vintage Black&Decker Pro Drywall gun. That clutch slips based on the depth of the screw head, which is set by spinning a "nozzle" in and out around the driver bit, so that the head gets recessed just the right amount. That was back when B&D still made good tools. We'd lock the trigger to keep the motors running and keep on zipping screws in as fast as we could. I used the gun again in 2012 when finishing the bonus room at my old house prior to sale, and the old girl still worked like a charm. There is some satisfaction to driving a drywall screw to exactly the right depth....
