Subtypes are an attempt to explain differences between people of the same type (example; gulenko's theory.
What I'm saying is that it could explain how some people in a "perceiving" type could be more judging and less perceiving than the stereotypical person in their type.
Let's take an SLI for example. And let's also make two assumptions; judging functions are left-hemisphered and perceiving functions are right, and irrational types are inheritally more right-brained, with rational types more left-brained. This would mean that the typical SLI would be right-brain dominant. It would also mean that he could spend most of his time in
mode. Good! Then guess what happens when he switches over to left brained mode, hey, he can use
! Brillant. But that is only ideal. Let's take a "less ideal" SLI example. He is also right-brained dominant. BUT, for some reason or another, both judging and perceiving functions developed in his right brain. What is this guy now? Sure we can say he spends a lot of time in
mode, but what about those logical processes that are in the right brain now? Maybe it's
? Maybe this perticular SLI relies much more on
than the average or "ideal" SLI. Thus, we could call this a subtype.