My personal experience is that these two inventories do not measure the same things exactly. The following exchange is with a reader: “Dear Hal, my name is Bryne. I have taken both MBTI and the DiSC tests. On the DiSC test I was a Melancholy Phlegmatic. As for the MBTI I tested as INFP/INTP. So how do I reconcile the results of these two tests? Does INFP correlate well with Melancholy Phleg or does INTP correlate better?”
My response: I’ve always been interested in trying to reconcile the Myers-Briggs and DiSC; in my observation they are NOT the same way of looking at temperament. For example I have a friend who, like me, is an INFP — both of us rate stongly for this type. However I am Phlegmatic Choleric (High S, High D) and he is a Phlegmatic Melancholy (High S, High C). So while we both tend to be laid back, my friend is much more analytical and critical and I am much more results-oriented (“results-oriented” is a relative term in a Phlegmatic!)
Since you are also an INFP we should share some of the same approaches to life HOWEVER because you are Melancholy first and Phlegmatic second, your personality would seem to differ from my friend’s and mine in many ways.
I realize this isn’t a full answer but it does indicate to be that the two types of inventories measure different qualities. Wish I had more; I guess I should put some more effort into this but I’m a Phlegmatic so . . . .