Using Minutes instead of Hours for Time Settings

With school starting tomorrow, I'm ramping back the kids' hours on the computer. The smallest time option I see is 1 hour. Is there a way to change that to minutes instead? I'm much happier with each child getting 15-20 minutes on the computer each night rather than an hour.

 

Is this possible?

Please note that this request is already added to our enhancement list. It is under consideration.

 

Regards,

 

Syed