I will I consider those who have extended MBTT as being a part of MBTT. Accordingly, Beebe's descriptions of the 8 roles provides the same type of thing that you find in Socionics. I consider KTT to be a bit different, but still in the MBTT family because its using the MBTI language that is based on MBTT. Berens' aknowledges this by how she combines the two theories together. If you include Beebe and Kiersey with MBTT, then you have a system that covers all the same basic aspects as Socionics.
KTT always throws me off, and I've been trying to figure it out off and on for some time. I accept it is pointing out a pattern that Kiersey for whatever reason wasn't capable of figuring out his own language to describe it and so he turned to MBTT. The only way he managed to get 16 types out of 4 temperaments is by working back from MBTT. However, I've thought that KTT might be more valid if it could discover its own language, and I recently realized that Bererns' has accomplished this even though she doesn't point it out clearly. She doesn't need MBTT at all to describe temperaments and interaction styles and with these two she can come to the same basic 16 types.
Since Keirsey modified the MBTI, keeping two of its factors (S/N, I/E), but
sort of swapping T/F and J/P into the new factors of Cooperative vs.
Utilitarianism, and Directive vs. Informative; I wondered if it would have been
better for him to use C, U, D and let's say "R" for "infoRmative", or perhaps
"Responsive" which is another term for it.
Also, since he believes that S/N is the most important, followed by C/U, D/R,
and finally E/I as the "least important", the letter codes would be put in that
order. The 16 types would then become:
ISTJ: SCDI
ISTP: SUDI
ISFJ: SCRI
ISFP: SURI
ESFP: SURE
ESFJ: SCRE
ESTP: SUDE
ESTJ: SCDE
INFJ: NCDI
INFP: NCRI
INTJ: NUDI
INTP: NURI
ENFJ: NCDE
ENFP: NCRE
ENTP: NURE
ENTJ: NUDE
The temperaments would become SU Artisan, SC Guardian, NU Rational and NC Idealist. Then it would have its own identity (using its own language). Notice also, it would be more symmetrical than the mapping to the MBTI scales. (NF, NT, SJ, SP).
The only problem would be the ENTJ being called "NUDE". Well, if you don't put it in Keirsey's order of importance, then it would simply be ENUD.
In her books on Temperament and Interaction Styles, she shows 3 orthogonal traits for each Temperament and each Interaction Style. However, both theories each borrow one orthogonal trait from MBTT(E/I, N/S). We can discard these borrowings because the remaining 4 orthogonal variables are all that is necessary to create the 16 types using absolutely no MBTT whatsoever. I just figured this out and I'm surprised that Berens hasn't pointed this out herself, but I have yet to see her do so.
If you're talking about C/U, D/R (mentioned above), Structure/Motive and Control/Movement; I believe most of these (in addition to I/E) would make it parallel FIRO's Inclusion and Control areas, even though the statistical correlations between the two systems always use E/I, S/N, T/F and J/P. C/U, D/R and Str/M are basically "twisted" versions of T/F and J/P. Both Str/M and Control/Movement pair dimatric opposites together.
Again, if he had used letters representing his own factors, then it would be as you say.
I have a theory as why the MBTI letters can be used to describe the KTT which is seemingly contradictory to MBTT. In MBTI Step II(I haven't seen Step III), the letters are broken down in the style of traits. According to Jungian theory of cognitive processes, J/P make no sense. If considered from a behavioral viewpoint, they do make sense. The letters refer to behavioral traits, and its from interpreting these behavioral traits according to MBTT that we infer the cognitive processes. Type code and cognitive processes are two different things.
So, this is why type code can be used to also describe KTT. Type code is a descriptive language that isn't limited by MBTT. On the level of traits, J/P and T/F are equivalent categories and so that is why its fair for Kiersey to use them this way. Kiersey was correct that, even though the theories contradict, the observations of the two systems correlate.
I'm just playing around with these ideas right now. I still don't know if Temperaments and Interaction Styles makes sense to me or not, but I'm trying to understand them.
Basically what you have are two sets of "four temperaments" systems cross mapped over each other. One is Keirsey's temperaments, and the other are Berens' Interaction Styles. Both together share one of each type between the four groupings they comprise. If anyone knows LaHaye's temperament system, where he uses the ancient Galenic names, and then blends them together (SanMel, MelChlor, etc); he ends up basically with 16 types (four "pure" types, and the 12 blends), and they can be compared with the MBTI types, if you know which Keirsey temperament, and which Interaction Style compare to which of the ancient temperaments. Berens herself does this with Social Styles, Personality Styles and DISC types in her article "Loning Interaction Styles to Other Models".