P6 Web Resource Leveling

Does anyone know anything about setting up Resource leveling in P6 web - the option is greyed out for my users?

I found the following information in the knowledge base, but was hoping for some additional information:

Level resources during scheduling

Mark to level resources automatically each time you schedule a project.

This is the only scheduling option that is saved at the user level, so will likely vary among project users, generating inconsistent results.

Note: This option is not available unless the Oracle Primavera Job Service is used for scheduling. Based on administrative settings, scheduling jobs are run using either the Web Scheduler or Job Service. The Web Scheduler, which is enabled by default does not provide the option to level resources when scheduling. To level resources, you must use the Primavera Job Service. Contact your P6 administrator for information and assistance.