The Project status is user controlled and not system controlled. We believe that the user has their own direct input into whether a Project is viewed as Not Started, In Progress, Suspended or Completed.
Here is an example: you could have a subtask under a Project heading that states "Create Project Overview Notes’ or "Plan Phase 2 of Project" etc. These tasks might be related to the Project overall but aren’t really part of the Project. If you complete these tasks, it wouldn’t necessarily mean that you had started working on the actual Project itself. In order to define the Project as started you have to manually change the status to "In Progress", in order to mark it once done you need to change the status to "Completed" and so on.