Why doesn't Project Status control if the project appears in the prompt lists of feeder systems?

I work in HCM and don't know all the setup of Project Costing and would like your feedback.  Our organization would like to limit the projects that appear in the HCM system based on Project Status, whereas PeopleSoft limits based on Processing Status.  For example, our Research Accounting department has a project status that has a processing status of 'Active' whilst the project is mostly operationally closed.  They leave it active until all final transactions are completed.  However, because it's active, users in HCM can still select the project, which they don't want.  They have the payroll analysis type setup