i hate to change course and disappoint... but enough from the experts. the major difference between the two performance classes is an. and all of those who chose to point fingers at me because they thought my equipment was illegal are dead wrong. i also have real concerns about the way the dairy industry is run. they like to feel smart, funny, beautiful around you. i have done the maintenance as scheduled. did not add or reuse the old battery adhesive and all closed and seems tight. 