I have the perfect solution to this problem.
All UPS needs to do is add one day to every package's scheduled delivery day.
For example, all packages scheduled for delivery in one day, deliver it in two days, all two day scheduled deliver in three days, and so forth..
This will give the preload over twentyfour hours to load the cars for delivery. With this much time all cars will be loaded stop for stop. The drivers will know exactly what's on their car, there will be no missorts, and nothing left in Center.
Drivers can start as early as they want and finish early with no missed packages.
Every driver will be happy, after all, that's the reason UPS is in business, to make drivers happy.
Of course there is a downside to this plan. The Customers will not be happy losing a day in scheduled delivery, and may seek an alternative delivery company. But hay, that's their problem, UPS will have happy, contented drivers.
Even the drivers who will have to be let go due to the decline in business will be happy. Those drivers will have all day and night to spend with their families, going to ball games, doctor appointments, dinner with the family, and whatever else that's important to them.
The few remaining drivers, still working, will have nothng to complain about, but then I'm sure they will still find somethng to complain about.. After all, that's what UPS drivers do best, they complain.