I have monitored decel cut-off hundreds of times and I can tell you that if you were in gear, foot off the gas maintaining speed (if not accelerating) down Vail pass there would be NO FUEL FLOW.
If I recollect downhill on Vail pass is ten to twenty miles. NO FUEL .
Since I actually live in flat lands and the state of accelerating while one's foot is off the gas doesn't exist, I can't say for sure that the system won't stay off indefinitely but I have watched it many times from 80 to whatever engine or vehicle speed brings about reset over a minute.
Bosch Master, ASE Master, L1
33 years MB technician