IZ: You are a witness at the scene
of a crime. May you be relied upon to give a detailed and accurate
report to the police? If yes, you might have more Si than Ni.
Since you asked a blog, there is always a happy chance you are not sceptical/paranoid enough for either type.
MS:
Ok, on the one hand, infj-zen and my ISFJ mom are at the super
introverted end of the scale, and I can tell she’s basing this answer on
that. On the other hand, if you keep getting one or the other type as a
test result, it’s also possible that you’re a shadow-functioning
extravert. An ESTP with the same functions as an INFJ, but you’re clearly an S-type, for example, so you keep testing as an ISFJ.