Hi,
I tried it now three times but I can not solve it on my own. I have edited the screen below and linked it to a new screen "Planning Months Settings".
Here I defined FCST 3+9 as below
Funny is if I enter design mode the months are allocated differently
I do not know why it changes it, but when I leave design mode it remains with nine actual months, and 12 planning months.
I tried to check in Administration sceen what happens and the monthly allocation is goofy.
Even as it worked already to set up the different versions by selectiong the "planning months" it is not working anymore. It looks like below after saving the changed planning months.