Three reasons:
1) To prop up the democratic doners and give them a reason to pour more money to the democrats
2) To cover up the rampant cheating in urban precincts. By being on the high end of the polls, they can say that any result is within the bracket of polling.
Your response is excellent. Did you forget reason No. 3? You only had two reasons.
I completely agree that if they didn’t fudge the polls those $1 million campaign contributions to Obama would stop. No one would donate money to what is a slam-dunk losing proposition. It’s all about the benjamins. But isn’t it always?