truthseeker100, I think this is always a risk, especially with certain types that rely on outside consultation/influence to determine the best answer. I always have my extroverted sensing friends take one or more tests, just to confirm, or see if they come back a different type because they felt different that day.
One good test I always have people take is found here: http://similarminds.com/embj.html That one kinda is longer, and asks some of the same questions multiple times and in different ways.