Actually, the CVG 767 flying IS "FedEx or UPS type flying" for DHL!
You may also have a skewed view of the ACMI business. Probably 60-75% of Atlas' business is scheduled, albeit on a quarterly or monthly basis. Most long-term ACMI and CMI customers have relatively stable schedules. For Atlas, those include DHL, SonAir, Panalpina, and AMC. Qantas and Boeing allude to stable schedules, but have more variation than the others.