I have never even considered this before, but when I entertained the thought it made perfect sense. I'm sure most of us consider ourselves somewhat "ambiverted". After all, no one is feeling "outwardly oriented" all the time, and vice versa. Even so, I had always balked at accepting the notion that ambiversion was more than a ploy for indecisive mofos to confuse everyone. I still feel you must be one or the other, but it makes sense that having a well developed aux function (which is necessarily of the opposite orientation of your dominant) could cause apparent ambiversion.