Just like to add to this since it's revived.
It also depends on how long ago said player played under said name, for instance I see Aquaman play with the {(SS)} tags now. So once he switched he would be racking up a score under a totally different name with a different points set entirely, he could of been high up before he switched and that's why other players are passing him now. Same goes for the rest of those on the list.
The only time Gametracker tracks you and your points is when your in a server, so you can have hundreds of hours on swbf2 itself. While only having fifty or so in a server, I know I from time to time leave my game on accidentally while it's just on the server list. So I have more hours then I do in a server
Skill also plays a factor to, a better play can get more points then another in a lot less time. Provided the terrible player doesn't sit in the server for hours on end, then he would be ahead obviously.
I know I re said some stuff, sorry for that.