Sanguine: people for people's sake
Choleric: people for tasks sake (i.e. "goals")
Supine: task for peope's sake ("acts of service", etc)
Melancholy: tasks for tasks sake
(Basically, these correspond to "express for wanted sake", where the "sake" is what we normally judge "people vs task" by, and the first part is basically I/E (how we approach people).
So if you're Supine, you might identify with "tasks", but the tasks are really to gain acceptance by people, where for the Melancholy, while being also loyal when doing things for people, generally approaches tasks for their own sake.
Also, as I've been saying, yes, being Melancholy in Affection may also skew things, for type does not divide interpersonal relations between surface and deeper relations. So a different tyemperament in both areas would end up having to be a type falling into one Interaction Style, yet have some traits not fitting the one for that type.
You're saying you're not Behind the scenes. What is it about Chart the Course that you identify with more? I would allow that Affection is actually your Interaction Style instead of Inclusion (I call this an "invert", and I've seen others here in the past who this seemed to fit). and if you're an SJ (you definitely do sound like an S from that standpoint description) that's "moderate" enough to end up in Phlegmatic in Control, then you could be an ISTJ Supine-Phlegmatic-Melancholy (SPM).
Have you looked at the descriptions for each area? (Inclusion, Control and Affection. It's one for each).