I will second Greg, and add that its not by chance that many of the control system devised by film, calibration and shooting system makers of the day used a Jobo to produce them. At the day, almost every pro studio had an in house Jobo unit, always on waiting to run a control before sheets and holders were sent off to pre press\production. In any case you do not need a photo sensitometer, or any other device for that matter to see how bad the negatives that come back from all three remaining pro labs in Boston really are, i suspect that is fairly close to the reality in most places.

Not to mention - when you want to scan or use the ENTIRE negative, and your name is now eileen cowin, and you do not use a Jobo system, you always have punch marks, along with a blotch of higher density around it... :|