Robr,
My example was to illustrate that if one were to not accurately determine the Zone I density representing the actual film speed in your camera, lens system , and meter the tendency would be to arrive a too high a density for Zone I because it would be very rare that any of us could determine a .10 negative density difference in the lower zones as it prints on enlarging paper.

The difference between Dmax and .10 is something that I could not determine by visually determining it myself in a projection test. The net effect by the time one saw a difference on a projection test such as you described would be too great a density and that would have the effect that I described of raising the high values prematurely onto the shoulder region of the film. I hope that I have explained myself to your understanding.