If the Costing Status is True, then Day End has been performed on that invoice. This means this invoice has been created in the AR batch directly, or written into the Retrieval file. If False then Day End has not been processed, and thus this invoice cannot be in AR. I wrote this in my initial reply on this thread.

Day End does not process an invoice in OE to calculate costs and copy to History, but not create the invoice for AR either directly or through retrieval, unless the system crashes during day end and preventing complete record creation and updating.