Wait, what are you saying? that you started out as a Mel-Chlor, and arew now a Mel-Phleg. Temperament is believed to be inborn, but just like type or any system, taking tests at different times, or even different tests can yield different results. If you're really INFP, then you're likely pure Phlegmatic, and Melancholy might simply be the next strongest temperament. A lot of people can have a three way blend of temperaments, so you might also be Phlegmatic-Phlegmatic-Melancholy, with only the first two corresponding to your type. But INFJ would be Mel-Phleg, and isn't that one of the other types you said might work for you? It's funny that as per our previous discussion, INTJ is another one that was mentioned, and that would fit Mel-Chlor.
So the ambiguity you face with humor temperament combination basically parallels the same ambiguity you are having with type. I didn't say "perfect" correspondence, but from what I have seen so far (both conceptually, by comparison to the Keirsey-Berens temperament/Interaction Styles model; and empirically by comparing people's type to their humor test results), it seems pretty good.