Managers are for dealing with personnel bozos, bean counters, senior planners and other mental defectives. Scorn floating point arithmetic. Don't drive clapped-out Mavericks. They prefer BMWs, Lincolns or pick-up trucks with floor shifts. Don't believe in schedules.
Planners make up schedules.
Frightened coders strive to meet schedules. Real programmers ignore schedules. Like vending machine popcorn. Coders pop it in the microwave oven. Real programmers use the heat given off by the cpu.