Require Password to Stop Client Service not working

Hello,

We run SEPM 12.1.5 and 12.1.157 clients. I set the SEPM Client Password Settings policy to "Require Password to Stop Client Service" and updated the policy, but the option to stop the Symantec Endpoint Protection or Symantec Client Management is grayed out on the Windows 7 client services. What might I be missing?

In addition, which service does this policy actually allow one to stop?

Thanks,

Robert