Is there a way to have the miner not hash during certain times of the day?
At the simplest idea of mine, was to hook up one of those AC timers that kills the power during certain times and then restores it at others.
Thats a very noble way and most effective.
You could also write a script that kills cgminer (and cgminer monitor) during your chosen downtime but ensure it is started during your chosen uptime. (don't ask me how to do it 'cause I do not know AND you've already got a good solution!)