Planning period variables for irregular planning cycle - opinions wanted!

Hi Planning Gurus!

I would like to have your opinions on the following situation:

Due to their business model the client wants to control the periods that are open for planning "manually".

How do you think this could be executed in a way that would be the easiest to implement and for the client to maintain?

I'm thinking using simply just 2 variables: ZPSTART & ZPEND type 0FISCPER.

Now I need your input on what would be the best way to maintain these variables? The use of default values for the variables is quite clumsy. Maybe utilizing TVARVC -table could be an option?

Any ideas are taken under consideration! Tell me about your experiences and how your clients have reacted to similar situations!

-m-