Anyone who scores 100% I, I have news for you. You're not. You can be a strong I - even a very strong I - but I seriously doubt you'd be hanging around this or any forum.
Whenever people tell me their #s - unless they took the test professionally before knowing anything about it - I'm skeptical. The result usually reflects that they know what the test is looking for, and they're idealizing some type in mind. Saying you've taken the test "hundreds of times" and have come out this way each and every time just strengthens the test-gaming theory.
The MBTI is inherently flawed, and I'm not exactly sure how to fix it - or whether it's even worth it to fix it. How you score depends on so many factors - how much you know about the test, how you feel at that moment (I always score as more introverted when I'm depressed; go figure), and whether you're answering as your actual type versus idealized type. Not to mention, the dichotomous nature of the MBTI is rather suspect. I behave differently in different situations, but the MBTI is not exactly designed to test that.