No flak from me Deema.
It's true that people doing commercial type work using window/ door tooling sets
often resort to the methods you speak of. If a larger run is in question, from time to
time they also stop and check if the resulting dimensions are correct or check it against a test piece...
No point in wasting a large amount of stock if something goes off-kilter, as no system is perfect.
This is not the kind of work I do, though. Usually it's one offs, small runs...
Over the years I have gotten very precise when sneaking up to a required height.
Spacers I use to get the cutter in 'the ballpark'. After the first test cut, I measure how much
I'm off the mark. In most cases one alteration of the height is enough.
I find this much faster than removing the tooling, adding/removing spacers and so on.
Apologies to the OP for straying from the subject.