I'm a J... and I know I have far less INTERNAL consistency than Ps. That's actually the reason why I need external structure. I've been in situations where I had no external stucture to refer to before, and I was far less able to make choices than most Ps. I could literally only react in very simplistic ways, and follow suggestions. I end up being passive/indecisive, and just doing nothing except waiting around and doing nothing of consequence until I know what's going on, and where I fit into it.
I think the answer, in MBTI theory at least, is yes.