I usually place in the top 12 or so (for some reason I'm usually number 11 overall @_@) and within the top 3 of sup point score cards. Personally, when I play sup, I really don't care about score =3= I mean, your whole role as a sup, is generally to keep your team alive with healz, so they can continue scoring and not wracking up cost. This generally means that you're enabling your team mates to continue to score well above what you're capable of (as the frag and damage points weigh heavier than sup points). The only times I usually score top 3 overall, is when I'm forced to be aggressive with a beru, draw gunning lands to their thorny bdsm doom.
TL;DR: Playing a sup defeats you're own score.
Also, the points a sup can obtain depends HEAVILY upon how their team plays and how the battle goes. If the front lines crumble, your capability to heal and support team mates crumbles with the front, while Rambos can continue to suicide rush and gain points @_@
Sorry, rant v.v