I don't think you should "adjust the (witness) price feed". There must be many ways to accomplish this.
In fact, you should be expanding accurate price feeds... and get into the oracle business. The witnesses should be required to provide a whole array of prices for the payouts they are getting.
I agree that adjusting the feed is not a good idea. I included it in the post to show that it was the "best option available" without a change to the platform.