Explain. I may have a similar approach. For example, in my list of fuctions (Ne, Fi, Te, Si) I do not have Fe. But of course I can create a "synthetic" version of Fe with Ne and Fi.
Well it makes sense that when one perceiving or judging function goes in one direction, it should be used with the opposite one going the other direction (ie. Ti and Fe, Ni and Se).
Let's take ESFP as an example. I seriously doubt any of them gives equal attention to all sensory data in the environment. Even the most P people still filter data through their internal standard to some extent (they're more likely to pick up on sensory data that is more important to their current thought process and unconscious tendencies). So they are S dominant with extroversion being the preferred direction for sensing. Maybe call it 90% extroverted sensing. 100% extroversion in a function doesn't seem possible.
I don't think it makes sense to call Se and Si different functions since neither of them seem to be theoretically possible. I'd rather call it sensing and include a spectrum of introversion to extroversion.
I do think that generally people tend to be 90% or more on either side, just due to our tendency to specialize. I doubt anyone could maintain any sort of balance in the middle of a function. So it still makes sense to think of functions as having a direction. Just not entirely one direction.
This is actually another reason I feel comfortable listing my function order as Ni, Ti, Fe, Se. Not all of them are pointing in exactly one direction. There is a bit of extroversion in my first two functions, and there is a bit of introversion in my second two.
Another thing: the MBTI system is flawed. We think of people that use T more comfortably than F as Ts, but I'm not an INTJ. Either the code should include less common orders, or we should throw out the code altogether and just list functions. There are definitely rules that apply to order of functions, but I don't like the rule for the order of the middle two functions. I think that should be thrown out.
People are raised in all sorts of different ways. If someone is raised in an environment where their auxiliary is constantly negatively reinforced and their tertiary constantly positively enforced, they are definitely going to be more comfortable with their tertiary than their auxiliary.
So what does "order" really mean? Does it mean comfortability? Or does it just mean MBTI perscribed order... If it means comfortability, the rules are too strict. If its about functions pairing in some sort of specific way, I guess we can use the MBTI order, it just can't be applied that far.