Derived Area - Account Assignment Issue - Cost Center should come from OKB9

Hi, We have 3 depreciation areas 01, 02,& 03. Area 03 is derived from area 01 minus area 02 and is posted periodically.

In OAYR for the areas, posting rule set-up is :

1. Area 01 -> cost center selected - CC comes from Asset Master

2. Area 02 -> N/A

3. Area 03 -> Cost Center NOT selected --> it should use the OKB9 default

When Periodic posting is run, the FI document posted uses the cost center from the asset master instead of the OKB9 set-up.

How do I fix this issue?

Thanks

Nat