What is the depletion layer logic for items under lot/serial number control in B2B Processing?

Summary:

I would like to fully understand how Oracle Cloud Costing determines the depletion layer in various situations in back-to-back processing.

Content (required):

1. A back-to-back sales order using PO # 123 for an item not under lot or serial number control - from my analysis, it appears that Oracle is using the Quantity Depletion Method that we've enabled (which IS FIFO).
2. A back-to-back sales order that uses PO # 123 for an item under lot or serial number control appears that Oracle is depleting the Lot/Serial number tied to the Sales Order via the back-to-back process (or perhaps it is still using FIFO but because the items are under lot/serial number control, the result was the same.)