Rolling Wave Planning

Reading about Rolling Wave Planning I would like to remember some basic links that have been useful:

Now I have a question, sometimes when I try to use this technique, I have some problems because my sponsor challenges me for more details in the complete plan, and my plan finalizes being so accurate.

It help us to identify hidden tasks to be done and ensures the execution will be as we think.

Then, when the project starts and something changes the execution of the plan cannot be exactly as I planned, so the change of the project baseline is unavoidable.

How can I handle this situation?