I have heard and have experienced such situation myself
Eventually I stopped after the 5th typing (3 on skype, 1 via emails/pictures + 1 via a video, oh wait there were also 2 MBTI ones, so that makes 7!).
Those were part of my curiosity, I also have a very hard time resisting my whims so I am one of those who throw their money in typology experiences/tests.... But overall it was really funny.
A lot of things have to be considered in typing anyway, and as much as I agree with the fact that a type is inborn, we also have to mind human experience and cultural/social malleability.
People do change a lot over time...