Why does on-hand depletion follow FIFO during movement requests?

Summary:

We are currently testing a POC in Oracle Fusion Inventory with Perpetual Average Costing enabled.

During on-hand conversion, we loaded a single item in a Subinventory with multiple transaction dates through FBDI. When we create Movement Requests (issue transactions), we observe that on-hand quantity is getting depleted starting from the oldest transaction date (FIFO like behaviour).

Validated on-hand back end table using query 'SELECT * FROM inv_onhand_quantities_detail'

We would like to clarify:

1. Is this FIFO like depletion standard in Inventory (even under average costing)?
2. Is this driven by Inventory Control/picking logic rather than costing?
3. Will the accounting always use average cost regardless of which receipt layer is consumed?