A couple of observations:
First, have you noticed that practically every organization under the sun is trying to credentialize themselves? Coaching designations, Professional Organizer designations -- a marketing research designation in my case -- where will it end? Is this a good thing? What does it all mean? Anyone?
Second, I feel very blessed to be an Extraverted Intuitive type when I'm writing exams. We think and respond quickly to situations, which gives a definite advantage when writing seven hour back-breaker exams. This particular one required pretty much non-stop production of words for the entire event, and I barely finished.
I spoke to several people who did not finish all the questions. Professional level exams are not designed for Intraverted Sensing types. These are people who need time to process their thoughts, and generally want to check their work carefully.
They don't do as well on exams at the graduate level. Not because they are not as smart, but because they are not as fast.
There's a wonderful story about just such a person on their third attempt at a professional designation exam, who decided to "just put anything down, like an idiot" and finally passed the exam.
A year ago I qualified to administer the Myers-Briggs Type Indicator (r) -- the exam for which had basically no time limit. It took me about three hours to write, but there were several who took five hours, just because they were careful in their approach. Now wouldn't it be nice to see more thinking like that?