As a person who has dealt with a LOT of INFJs (specifically ones who thought they were INTPs) on this forum (And in general), I can tell you that you are making some very risky assumptions here.
Same here, dude. If you want to start laying claim to "experience" and how you seemingly have had more than me, well, I've been active on a number of MBTI forums for the last five years and have moderated one for close to four, and probably have somewhere with the range of 30-35K posts on MBTI forums, at least half about MBTI issues. I'm not saying what I am saying without having at least as much or likely more experience than the majority of people on these forums. I also have quite a number of INFJ friends, some of whom have wondered if they were INTPs, and happen to have very strong Ti tertiaries.
But I never really liked the "typing" threads, whether it's for particular members or celebrities. It's a lot like people cherry-picking certain details out of the haystack to support their predetermined view of someone... and it also ignores the fact that MBTI is a theoretical system that is being applied to the data rather than completely generated from the data, so people won't necessarily fit within the rules.
For one, INFJs don't always know their answer, they are human too, they also need time to take in information and let their Ni get the lay of the land. Ni is actually the slowest function when it comes to building an understanding, it needs to wait and take in a lot of information before it can freely move through it all. In that period of waiting, you are going to see a lot of Ti based questions, because their Ni is being built with a lot of Ti-Se components, that their Ni-Fe is going to Synthesize into something more.
That's not actually what a majority of INJ's have told me, albeit some of them being INTJs. I specifically have had some very intelligent INJs describe their view of Ne vs Ni, and correct me on the matter in the areas where they felt I was off. The most typical description I have received from INJs is that Ni is a "connect the dots" picture, where you look at the data in front of you and you automatically see the rest without having to connect the dots. It's a way of seeing, not of rationalizing... otherwise it would be a judgment function.
What you describe is an INJ without much Ni, and lots of Ti -- you're determining what data should be where using a Ti process.
I will consider the possibility that your total picture of things might change with the more data you get.. but now you are specifically describing a Ti+Ne process! That's exactly what ITPs do, in order to develop the big picture... collect lots of points of data and rationalize through the connections to see what we get.
When you see an INFJ articulating their Ni while Ti calibrates it, then you are right, Ti is supportive, but that is not always obvious in text. INFJs are also not always going to be pure on target, they often go on tangents too (some much more than others), which can look like Ne, even though it isn't.
Actually, N is "fuzzy" whether it's Ne or Ni. So I think INFJs can describe the big picture and be off on the details. That seems to align with what you are saying.
There are many many many different models of INFJ, many of which kind of look like how some of the other types (Like INTPs and ENTPs for instance) are "Supposed" to look.
Yes, I'm well aware of that. Each type has a number of "typical patterns" that tend to describe them. There could also be more unique blends/cases that don't typically show up, but it doesn't mean that one cannot probably look at each type and note 3-5 "typical configurations" or patterns that occur within that functional framework.
Drawing boundaries like you are doing, "this type acts this way", "and that type acts that way", almost always sets you up for misreading people.
Please. This is YOUR overemphasis of detail that is attributing ideas to me that I do not actually hold. You are misreading me.
Go to my prior paragraph -- there DOES tend to be a "few basic configurations" within each MBTI type that are represented ... but you still have to look at the unique person. I'm an INTP with atypically high Ni. You are preaching to the choir and trying to read me as some sort of exacting SJ type here, which I'm not. I am not talking about using particular details as "clear-cut" identifiers of type, a procedure I find faulty. Sorry if I somehow misstated myself, I'm just kind of surprised by your read of me.
And trying to read a person via text is probably the worse way you could possibly do it. There is always something you are not seeing, text is only the end result of what people are doing cognitively behind the screen (hence people once thinking I am an xNTJ or sorts, all they see is me pushing information, they don't see that My Ti is being impinged first, which makes me want to come out and correct them.)
Again, please. I totally agree with you, which is why I hate typing online.
You need to see someone IRL to have the best possible shot at grasping them.
I'm telling you this because I have made many of the erroneous assumptions you are making in the past, and it has nearly always screwed me over in the end.
Thank you for the advice. However, I'm already well aware of the typical flaws in rationality and especially within MBTI typing, and I'm still saying that types usually express themselves within a few particular instinctive patterns. (Do you understand what I mean by this? It means it's not concrete data points that automatically expose a type, it's the relationships between the typical data points of a person -- the principles of their behavior, the broad patterns, and how they relate.)
These patterns still have to be examined and confirmed just to make sure the pattern is not being misread, but it's not a lot different than when the police cycle through those mugshots and certain faces can be categorized as having similar (even if not exact) relationships between the designated points of the face used for identification. If we would be unable to do this with MBTI, then it's almost a waste to even bother with the system; these systems basically describe patterns that we see which one we most align with.
I hope that explains my thinking/approach far better than my shorter post did earlier.
it coming across this post. Very much what I was looking for. 
