For me personally I don't want to get every little bit of power out of an engine. On a hot day it doesn't take much for it to go lean and then you start to damage your engine. I'd rather run it a little on the rich side and fly it rather than have it go lean and repair it. I like to run Byrons 10% nitro with 20% oil. With the added oil I'd rather clean it than repair it. Just my way of thinking.