Project manager workload reporting

We currently report workloads of our project managers as a function of how much revenue they are carrying and the gross number of projects. However, this is far from perfect. When we have large projects we batch the projects to have a single project with a single receivable, and then many projects where the actual work happens, with no receivable. We do this to simplify the invoicing as well as to manage smart projects with multiple source languages. On these projects, we need to have a lead PM on the primary invoicing xtrf project, and then we have multiple PMs on the other projects. As you may imagine, this leads to reporting where one PM has tons of revenue, and the others have none. It's not awful, but it's a challenge. Also, we have been trying to add more project coordinators, but XTRF doesn't seem to allow for an easy way to report on project coordinators.

Sorry for the long intro. But my question is how to others report on Project Manager work loads? What successes have you had with using XTRF and/or what work around do you implement to get a handle on how busy they are?

Thanks for the input!