"To go from 17% oil to 22% needs 8.2 ounces added per gallon, or 2.05 ounces per quart."

Are you sure? A gallon is 128 oz. so 1% is 1.28 oz. To go from 17% to 22% is a 5% change. 5 x 1.28oz. is 6.4oz. 1/4 of that is 1.8oz. What am I doing wrong?

Jim