Change the point system for the Chase competitors for the last ten races. Isolate them away from the others. The chase competitors that gets the highest finish get a set number, 2nd competitor 10 points less, 3rd the same and so on. The way it is now, two DNF's and you're out. This would keep the competition for the Chase closer to the end. The other 31 drivers stay on the same point system during the chase to determine 13th and down.