I took an Easton Arrow Class and I ask the same question. The Instructor won a gold medal in the Olympics. I can not remember his name, but he was the guy who missed a nice buck on Monster Bucks with realtree. I think it was 2 or 3. He said and I Quote "F.O.C mean Fricken Over Complicated" He used a different word. Who knows I like 10% and 15% I fond his comment intersting.