TFO is right, I went back and looked at your post. Avarial, artifact character bonuses do not stack. You can make two artifacts, one with +6 for your PC in each category, and that would stack. Your PC bonus of +3/+3 stacks with your Artifact Bonus. So the best you could get in this case is +9/+9. That is until you create an Artifact of higher level.
Oh, and I'm updating the lists. PL caps have been redistributed as if we lost a player, because we are short on people. You should be able to see your new Cap now, on the lists. I also rolled a lottery of excess PL around, you can see the results in the lists.