TBH, it gets a bit crazy and confusing to use that method. Personally, I think Harold Grant's Cognitive Functions are basically garbage until proven otherwise. There's no evidence out there that's really deeming functions authentic. I don't use this as a primary typing method, I go by dichotomies more...but I'll still entertain others' methods and do things from their own preferred angles if someone else doesn't see things the way I do generally. Now that I've established my actual stance, I'll commence with approaching from your angle here (just bear in mind that I don't actually firmly believe in half the shit I'm about to say, since again...I think functions are utter shit until proven otherwise).
Your statement contains the presumption that introversion and extroversion are determined by strength of a function in a stack:
[Ni] Lv 5
[Te] Lv 4
more extroverted than
[Ni] Lv 5
[Te] Lv 2
...to illustrate / lay out the concept in a more visual manner.
However, there is really no finalized or conclusive evidence either for or against whether or not each function axis itself would actually be operating on a spectrum (or in other words, basically x2 Fe users, both with Aux Fe, but one more prominently Fe than the other)
Person 1:
[Fe] ----•--------- [Fi]
Person 2:
[Fe] -•------------ [Fi]
So, I mean...what a mind fuck to try to type anyone through that...I don't really feel like getting into all of that. It's an impasse without actual research involved, so all we would do is run in circles around inconclusive hypotheticals without any real answers in the end.
Yet, if we also examine each of the function axes in their dominant state, there is no differentiation between Ne Dom and Extroversion--at least, by definition. This is because we are talking about cognitive extroversion (which is likely easiest to summarize as "the focal point of a person," and whether that would be on the outer world or inner.) Why would anyone spend the majority of their time in their Aux fcuntion naturally rather than their Dom? There is therefore no separation between Cognitive I/E, Functions (when Ti = cognitive introversion and Se = cognitive extroversion since the directional flow is toward an inward or outward state which is entirely overlapped with the baseline definition of cognitive I/E), or Dichotomy I/E...by definition. Sadly, in reality, this turns out being flawed and people don't always align so well in reality because Harold Grant's Cognitive Function Stacks are too restrictive and impractical, which means you can thus be an ISTP with Inferior Ni.
tl;dr
Your Aux function is not what determines your I/E levels according to theories anyways, btw.
It's better to type in each system separately in order to obtain accuracy.