I've done this experiment once. I think I used Tmax400 and XTOL for this test.

Take an image with full range of tones. Have a gray card in there also.
Shoot it 1 stop over, 1 stop under. 2 stops over, 2 stops under. Then repeat the process 2 more times.
Develop each with what the chart says. +20% dev time and -20% dev time. Then +20 MORE % and -20 MORE %.
Print each image so that the gray card looks identical.

Except for the fringe cases where -2 stop exposure and least developed AND + 2 stops and most developed, all results looked basically the same. I really had hard time telling them apart.

Try it.... it's amazing how flexible and forgiving this whole thing is....