Wouldn't it be dependent on the speed you are traveling? If for instance you are traveling 75 MPH on the interstate down a steep grade, if it downshifted to M5, the rpm's would shoot up quickly and potentially to an rpm near red line whereas the gradual down shifting allows you to bring it down gradually. Obviously that would be different if you were travelling at say 55MPH. Additionally, if you are using cruise control, it will down shift automatically to keep you at the speed that is set.
I live in the mountains of Colorado and travel on I70 regularly over passes. It does a good job simply using cruise control.
I live in the mountains of Colorado and travel on I70 regularly over passes. It does a good job simply using cruise control.
