Gornaut, I agree that the maths are straightforward . But I also agree that it can be somewhat unhelpful without some intuitive understanding of what is being described. I did find your diagram very helpful as to what the point of the calculations were.
I went back and reread post #5 which does indeed explain it very well. In light of that explanation (and CliveL's remark "nobody apart from the engine stressmen cares a stuff about those distinctions"), isn't the phrase "produced by" a little misleading. I can understand that 63% of the thrust is transferred to the aircraft through the inlet duct. But, couldn't I just as easily calculate and say that (obviously I'm making this up): 23% of the thrust is transferred through attachment bolt A, 15% through attachment bolt B, and 25% through attachment bolt C. I don't see where I would ever say that 23% of the thrust was produced by attachment bolt A.
This discussion (which is fascinating!), sort of reminds me of the story of the man who upgraded his car with: a carburetor that claimed fuel savings of 40%, spark plugs which saved 30%, tires that saved 30%, and an exhaust which saved 20%. He had to stop every few miles and drain his fuel tank.