Using role planning & assignments for load analysis

I want to analyse the role loading for all my projects: in execution, in planning and in initiation phase.

For those in planning and execution I have assigned role units at task level.

For those in initiation I want to plan at Project / WBS level, so I use "Plan resources" from P6 web.

Extract form P6 help:

Planning Page

Overview 

The Planning page is a valuable tool for quickly and easily establishing resource demand on a proposed project without the need to perform time-consuming resource-loading on a detailed project plan. This high-level allocation data can be maintained through the life of the project and referenced when planning resources at a more detailed level. While resources may not be assigned to specific activities at this point, a portion of their time can be allocated towards the project, which informs project managers of the intended commitment of the resource to the project. This helps to avoid overallocation of resources during project planning.