Changing branch plant in sales order resets category codes?

Hi,

I have a question on changing the branch/plant in a sales order.

I create a sales order for a branch, and manually change the category code 5 of the order (SRP5).

Then, in some cases it's necessary to change the branch in the order detail. But the category code gets reset, and the value is changed to the one in the item/branch for the new branch.

Is this working as designed, o is there a way to keep the category code that was entered manually before changing the branch?

Thanks a lot.