I've noticed this mode after a few weeks of driving (didn't know it had a name) and have become pretty good at using it and keeping it there. I can definitely feel when the car is going into this mode, a drop in noise (which is hard to detect in an already quiet car!) and a gentle drop in power. I've found that it triggers mostly when I am on a flat surface running at speeds of 45-60. I can sometimes manually 'force' it (or maybe I'm tricking myself) but most of the time it starts after 15-20sec of no pedal movement and constant speed. I've treated it just as I would e-mode...it won't stay in this mode if the accelerator is pressed to hard.