EPA is the limit you set for each direction of travel by the servo. On my car, the servo can turn 82% to the left before it hits the steering block stop. If I left it at 100% it'll wear on the gears and parts trying to turn farther than it can. The dual rate of 100% would mean that you are turning the full value of the EPA. And don't worry if the Left is 82% and the right is 77% or something. Few cars are symmetrical.