Oracle has restricted the use of Cross Charge on a capital project, when provider organization is on a different operating unit than the receiver organization.
The reason is due to accounting issues that might be raised, would that functionality be allowed.
When expenditures are costed in the capital project system will debit a CIP account in each one of the of the organizations, which may be in different OU's or even different SOB / ledgers.
Since a provider organization would get a credit with a cross charge (inter company revenue) it is expected that the cost will charge a Cost of Sale account and not a CIP account.
When you run the capitalization process in the project owning OU, the system transfer the asset lines from the project to Fixed Assets. Each asset line carries to FA the information about its original CIP account. Running the accounting process of FA of the owning OU, would debit the asset balance account in GL of the credit the CIP account. Since CIP accounts come from different OU, they might even carry a different chart of accounts, and cannot be posted into the receiver org ledger.