Why do I keep getting "rare" byes in the Grand Arena?

Each round gives you up to 2000 points for setting defense and offense, plus a 1000 pts for the win. Times that by 3 rounds gives you 9000 pts, plus I approximated a 1000 points for the missed feats. I didn't add in the 1000 pts you do get for the bye, so it's only around 9000 pts lost per bye.