Actually, many INTP's may score high on Fi related questions without actually using Fi as a cognative function. A lot of Fi based questions are very hard to answer because it's a very unconscious-like cognative function and people are easily biased into answering in favor of the Fi, because it seems like the right answer. But the difference is that you would reach that conclusion using your Ti, thinking that that is how you should answer. Whilest it has nothing to do with Fi, feeling that it is truth.
Especially on my firsts tests (probably because I wanted to secretly depict myself as more awesome then I already was), I usually scored prety high on Fi, not until much later and delving into what Fi really was did I realize I don't use it at all.