I don't use the button, he just change the gear after 2500 rpm. I prefer to use the standard mode and if there is too much ice/snow I take the wife's ML. If I am in a very bad situation I remove the ASR because the system is lost and I manage myself: snow tires, low gas in 2nd, low speed, very careful in the corner. Many miles on snow with rear-driven cars in Switzerland, not any accident.