Windchill Change Management

We have been running Windchill for the last year in a true multi-CAD environment (Inventor & Creo) We are beginning to implement the Change Process. As we take a deeper dive into it, we are somewhat confused about setting Dispositions in the Affected & Resultant Objects tables.

How do you interpret the OOTB columns "On Order", "Work-In-Process" & "Finished" in your environment. Are they associated to real life milestones in the manufacturing process.

Secondly, I question about the OOTB drop down values such as Use Existing, Convert, Not Applicable. What real life