New settlement Rule (copy of superior rule) in spite of message KD050

Hi'

I have a setup where WBS level1 is a Billing element.

WBS level 2-3 are Acc. elements

Settlement Rule for Billing element are maintained manual.

Settlement Rule for Acc. elements are copyed from superior rule.

I have generated Settlement rule, the projects are "running", the first settlement has been sucesfully completed.

Now the organisation is changed and the Settlement rule should have a different Profit center.

I put an end period at the Settlement rule at WBS level 1.

I create a new Settlement Rule at WBS level 1.

I put an end period at the generated Settlement rule at WBS level 2-3.

Now I want to generate Settlement Rule again at WBS level 2-3.

That is not possible because a settlement rule already exist.

What can I do to get a new and updated Settlement Rule at WBS level 2-3?

Thank you in advance for advice!

Kind regards

Lone Würtz