Define default Req approval rule for Cost Center not already defined in another rule

Summary:

Our US BU is setup to route based on Cost Center (Department) and this is working as expected.

However recently it was discovered that Finance side business was adding new Cost Centers without alerting either Procurement Business or IT. Hence, Requisitions submitted fir these new Departments were skipping the Preapproval Header Hierarchy stage and going right to manager approval in Header Hierarchy stage. Buyers were first seeing these Requisitions in Process Requisition Lines.

The requirement is for a rule that will catch Requisitions missing Cost Center.

Tried adding a new rule and if we have a Requisition missing a Cost Center it works fine. Unfortunately for Requisitions where we already have Cost Center defined, it is also being invoked - so it is requiring approval twice by the Buyer.