I took the Organizational Behavior DSST a few weeks ago and passed it. I'm still not sure by how much, but the Navy College Office on my test has a program and scanner that gives a pass/fail indication for the test before they ever send it off.

I took the DSST before I had discovered InstantCert, but I found the study material in the Official DSST Guide to be quite helpful. The questions were also a good indication of if you'd pass or fail. It can be viewed here:

http://www.petersons.com/pdf/free/DSST.pdf

Incidentally, I also used the DSST Guide to study and pass my Principles of Management (CLEP) and Human Resources Management (DSST). I just studied the overviews for:

Introduction to Business
Introduction to Supervision
Human Resources Management
Organizational Behavior

That was all I needed to pass all three tests. Hope this helps.