Currently, the rate for a role can come from a global, company or project level. When you first create a project, you can control where it pulls the rate table from.
HOWEVER, if you report on tasks assigned to roles but not individuals, and/or that don't have hours logged against them, you cannot show the rate that will apply once work commences.
There should be an 'effective rate' column in the report engine that knows where Workfront will look for the hourly rate once time is logged against the task, and display that information.
