You fail because you are trying to predict something using MBTI. Its not meant to be used that way. It is not a tool to predict someone, it is a tool to help understand intentions, motivations, strengths, weaknesses.
First of all, I agree with poki that MBTI's use is not to predict.
Ideally, it should be used for what poki suggests.
But then I take issue that MBTI can even be used for such,
since I do not think that "pre-packaged" function orders are what is true of people.
MBTI was created for the masses.
It was not created for accuracy.
If either of you are into research, Google
Singer Loomis SL-TDI
Singer and Loomis decided to test the MBTI assumptions and MBTI failed.
Here's an example of a technical expert's profile:
Introverted Thinking Dominant
Extravert Sensation Auxiliary
Extraverted Thinking Auxiliary
Introverted Feeling Mid-Mode
Introverted Sensation Mid-Mode
Extraverted Intuition Mid-Mode
Introverted Feeling Least Developed
Extraverted Intuition Least Developed
Here's an example of a team leader's profile:
Extraverted Sensation Dominant
Extraverted Thinking Dominant
Extraverted Intuition Auxiliary
Introverted Feeling Mid-Mode
Introverted Thinking Mid-Mode
Introverted Sensing Mid-Mode
Extraverted Feeling Least Developed
Introverted Intuition Least Developed
Immediately you will notice the function order possibilities are now there in the SL-TDI,
that are not permitted in the MBTI.
If you are into serious reading about Singer Loomis SL-TDI:
www.haskayne.ucalgary.ca/haskaynefaculty/files/haskaynefaculty/singer-loomis.pdf