Cover drivers are different. At my center they use them when too many people call in sick, or like Amazon Prime day. They aren’t used to reduce Full time drivers overtime, ever. They also would never reduce the volume on a Monday, and cause routes to be cut on Monday. I personally don’t have a problem with cover drivers. We have about 5 of them, and i understand that UPS cannot control people calling in sick, so they have to have staff available to do a route, in a pinch. This is much different than a full-time position, doing the same work for half the pay, and no protection.