I've been looking at various LII descriptions, and I think I've noticed two different kinds of Ti. In an economics class that I took, the textbook classified all economic theories into two categories: normative theories and descriptive theories. A normative theory tells you how things ought to be. In this sense, it is evaluative - it's a form of opinion or judgment. A descriptive theory tells you how things are. In this sense, it has no opinion, it's aim is simply to describe things. I think that I can classify some descriptions of Ti into two similar categories.

For example, some LII descriptions talk about what I would call evaluative Ti - it is a form of Ti that evaluates the logic of the situation, idea, etc. Consider these descriptions:

The LII naturally assesses statements, opinions, and actions in terms of conformance to certain principles. These principles may in practice be rules of thumb based on experience, but LIIs will usually appeal to more general, self-evident reasons, if the need arises. The LII is most engaged in communication when he is critically analyzing people's decisions and actions as well as how they generally are or are not consistent with certain pre-established goals.
They are skilled at understanding, generating, and criticizing logical arguments and instilling their views in the people around them. Their friends know them as people with well-organized thoughts and opinions who know what they think and can elucidate their ideas to others
Clearly, some aspects of these descriptions involve some form of logical evaluation - this form of Ti is opinionated, judges things, etc.

Now consider these forms of Ti, which aim not to evaluate the truth of things, but to describe things (and, in this sense, I call this descriptive Ti):

She understands the essence of a situation by creating a model for this knowledge in her consciousness that corresponds with her experiences. She’s guided by the universal ideas she’s found and comprehended, regardless of others’ opposition.
Analytical mentality. Ability in all to find a relationship of cause and effect. Propensity to abstract, system thinking. Ability to separate the main thing from the minor. theorizing, propensity to brainwork, construction of abstract models.
The aim of this kind of Ti is not to evaluate reality, but to model it.

In conclusion, this does not mean that these are the only two types of Ti, or that this is the only way to categorize Ti, but they seem to be two different themes that appear amongst Ti types. And I've noticed in myself that I tend to look for patterns, models, etc. more than I attempt to evaluate things, so this might be a pattern that could lead to a new subtype theory.

Jason