Hot to prevent Pivot Table overriding Manual Data

Hello,

i have the following problem.

I have a Pivot table with an manually added column at the end, where i do some manual calculation.

Every month i need to update the pivot and it will get an extra column because of the extra month.

How can i prevent, that the pivot table will override my manual data? Is there some kind of setting, that the manual column will be moved to the right if the pivot expands?


Would be great if someone can help!