Parental Controls resetting (not saving)

Machine: iMac 2.3ghz Core i7

OS: 10.9.5

I have been attempting to set up Parental Controls on a user account for my children to use while homeschooling.

Through several iterations, I have selected my preferred settings (e.g., Simple Desktop and certain permitted websites) with the padlock unlocked (using my Admin Pwd). I have then locked the padlock and logged out of the user and logged back in.

Invariably, all of the Parental Control that I had selected were missing and reset back to the defaults.

Advice?

Thanks!