Possible Clues:

• Odd thing to convey to those workers who spend their days in bed
• Those who never do a day's work
• Late assignment
• Workforce during the wee hours
• After-hours work schedule
• Near end of August transfer part of the workforce?
• Turning over in bed to see workers in the dark?
• Staff in the habit of sleeping
• Late for work?
• Moonlighter's work period