It's not true in my case, @MasterOfAwesome. If I judged more than I perceived, I would be a J. The fact is there is no way of measuring whether one uses "more N" or "more T" unless you are talking about the strength of that person's preference. For instance, the difference between my preference for intuition over sensing is greater than that between my preference for thinking over feeling. Yet I definitely prefer N and T, and I am also an introvert with a strong preference for P over J. Therefore I am INTP. The fact that my N preference is higher than my T preference does not change that.
And I'll tell you what my problem with the functions is: They are not supposed to be used as a typing method. They are to be used to look under the hood after you find your type and possibly explain how you work, not to find your type in the first place. The functions are nothing more than symbols that are supposed to explain theoretical motives for behavior. They do not actually manifest as distinct behaviors, as one would have you believe when he says something ridiculous like he "uses" Ne as if it were some kind of tool he had conscious access to. No, he doesn't. You don't "use" functions like that. If anything, they are the things running in the background and they all work together to form a type. They aren't separate tools you draw out and use individually, not things you use "more" or "less" of. You think when the situation calls for it, sense when it calls for it, etc.
As if boxing yourself into 1 of 16 4-letter types doesn't leave enough margin of error, there is no way you are going to be able to find yourself perfectly and rigidly matching up with a distinct line of 4 abstract cognitive functions in a deadlocked "order." If it were that simple, then I as an INTP could never do anything attributed to the "Se" function because I don't "have" it. But that's not what it means and it's not how it works. The functions are often taken too literally and seen as more than what they are. So you understand that my problem is not with function theory itself so much as its misuse. (Though I am skeptical about the reliability of function theory itself, I do believe it can be useful when taken for what it is and nothing more.)
My point is that if the OP is an ambivert, that's what he is. If he's an introvert, that's what he is. And he shouldn't feel that is wrong because it isn't perfectly consistent with a strict interpretation of function theory that cannot possibly be perfectly consistent for the billions of people on Earth. It's a SELF-improvement tool after all. So if it doesn't work for the self, what good is it for?