The double intro/extraversion thing is why I like to distinguish between NiFe-Ti and NiTi.
NiFe-Ti reads as "standard NiFe, but strong Ti usage is a key component". Ti may be stronger or preferred, but Fe is still conscious and matching up with Ni to create the impression of NiFe-classic.
NiTi to me implies that Fe is out of the picture, and that the individual is almost entirely running on their introverted functions. FiSi and SiFi have that distinct soft rambling speech because Ne and Te are out of the picture, unable to shake things up. FiNe-Si and SiTe-Fi have better use of those functions to sort of check with the Objectosphere (dibs on that term) and keep things a bit more active, despite prominence of Fi and Si.
Okay, that's exactly how I was reading it until last week. The chart shows Fe as being unconscious for NiFe-Ti. I thought it should only be unconscious for NiTi. I like that distinction, personally, as it accounts for the range of variation we see.