Parental Controls process/daemon

The patental controls time limits for OS X are a bit flakey.

They worked fine for a while, but recently my son's time limits aren't being applied anymore. This seems a common enough issue.

It started working for a couple of days after the 10.10.2 update, but I think this may have been more to do with the reboot than apple fixing a bug.

I'm running Yosemite, but had the same issue in Mavericks.

Does anyone know which process handles this task? I can then delve into the logs to see if I can find any errors, or maybe write something to restart a service.

Scheduled reboots have been said to fix this, but that is so unelegant. There has to be a smarter way.