Sales Order Relationship to PCBU and Managerial BU needs to be clarified

We have a sales order which is generating an SFO event incorrectly. The Sales Order header has the Business Unit of 'CK Power'. The line is shipping from an inventory org which has a PCBU of CK Power Products and the managerial BU of CK Power. This should not generate an SFO event because its shipping from an inventory org that belongs to the same BU of CK Power. We cannot setup SFO rules for the managerial BU of 'CK Powrer' because its not a PCBU, its only the Managerial BU.

If we switch the BU on the Sales Order to the PCBU of 'CK Power Products', the AR invoice tries to create under the PCBU and not the corresponding managerial BU of 'CK Power'. It was our understanding that all transactions outside of inventory should be performed under the managerial BU's. This is working fine with Purchasing.