The explanation page for the Thoro-Patterns is in the intro section of this site. The top in this case is the neg 6, and the sample size doesn\'t reflect horses by what figures they ran, just what pattern. I will guarantee there is no-one else in there with both that pattern and a top of neg 6.
So yes, you have to take into account things like how big the top is, and that he may not have been fully extended last time, when looking at the TPs.