The system works the same for granting XP, yeah. I'm not sure about that bug though. I doubt anyone's looked into it on our end since I haven't heard about it before. Note that NPCs were never supposed to have the /same/ amount of experience as you in KotOR1. Throughout the game, they're supposed to be earning 80% of what you earn, if I remember right.
-Akari
I'm surprised you havn't heard of that bug before as it was quite widely discussed when KotOR came out. A lot of people put off leveling up so they could take more jedi levels and found that thier sidekicks where getting less and less experience.
This could effect your prestege classes if they work the same way as swiching to a jedi class did in the first game.