Some people can be very hard to type, due to certain circumstances, maybe stress, a diagnosis, being unhealthy, etc. Things like this may not make someone fit under one type, and we can contradict our type stereotypes, or what people would expect of us. People act entirely different on little to no sleep as well. Everyone has their good days and their bad days. But I believe that people's dichotomies have to start and end somewhere. Even if we may change under certain conditions, there are certain things that stay constant, preference-wise, functional-wise.
I had thought of a what-if scenario, someone only having one possible preference i.e. Ixxx, Exxx, xSxx, xNxx. When typing other people, we don't know the intricate process behind how they take in the world, we are not them so when typing someone else, I can see that type of typing making sense. We may see entirely different sides to one individual that throw us at a 180. But with someone who we know very well, or self-typing, that's about where I'd end that type of typing. If someone has been into typology a long time, that just takes them back to square one and leaves more questions than answers if anything. Even being newer to typology, while it's good to have an opened mind to the possibilities, if someone pins themselves as that kind of type, then I am not sure how far they will get. Taking it a step farther, having no consistent preferences or functions whatsoever, I don't think it would be an effective way of pinning someone.