just an FYI, im not sure if anyone had the same issue as me, but if you decided to schedule an upgrade for your MX in less than a 5hour window, the update will take effect 5 minutes after you validate the schedule. if you schedule it over a 5 hour windows, the update will go as planned. i scheduled 30 MXs at 4pm EST to be upgraded at 7pm EST, and the update took effect 5 mins later causing a mass outage during business hours. a case is open with Support.