Shouldn't that statement be:
"To make the same power (as 98) with 100,and have the correct mixture, you need to retune the engine as the 100 uses 2 percent more oxygen therefore the engine will run leaner." or something like that
Please correct me if I'm wrong, Jim. Putting 100 in a car tuned to run on 98, 95, or 90 will not make the engine run leaner, it just wont burn all the available fuel.