TOPIC: Project management plan and its subsidiary plans!

Explanation: Every project plan is a subsidiary of the Project Management Plan. The Project Management Plan is finalized when all its subsidiary plans are developed and approved. The Develop Project Management Plan is the last planning process that is performed during the planning phase of the project.
Reference: PMBOK Guide 5th Edition, pages 72, 73
please if someone can explain to me how is the project management plan to be the last document in planning process meanwhile its an input of all subsidiary plans? I need a logic answer which convince me as I'm confused about this matter since I started studying but i tried to manage it as it is to go ahead but actually I feel that this topic needs more explanation and more effort from our help desk.

Hi Hazem,
You can think of it as the project management plan is a always a "work in progress" during the planning phase. for example, when you are doing the scope management plan, you finalize the scope management plan, and then add it to the project management plan. the updated project management plan will then be an input to your next planning exercise which will add/update another subsidiary plan.

this case would be the same for some other documents, for example, the WBS and the WBS dictionary, these documents will be created in the create WBS process and will then be both an input and output to other processes which will keep updating and adding details to the documents.

Thanks Ahmed, yes Its true but is it not better to call the early stage of PM plan a primary or initial PM plan and later we call it updated PM plan to eliminate the confession ?