Lot Numbered Assembly Item with Multiple Receipts in one Lot Number, what is the costing method being followed?

Scenario:

1. Create a Lot numbered Inventory Item

2. Create a Purchase Order for the said item dated 12/1/2011

 -- Qty: 300 

 -- Unit Value: 0.45

3. Receive the Purchase Order, Enter Lot Number = LOT1

4. Create another Purchase Order for the same item dated 12/5/2011

 -- Qty: 500

 -- Unit Value: 0.27

5. Receive the Purchase Order. Enter Lot Number = LOT1 (note that the Lot number is the same as the first receipt)

6. Create an Invoice for the same item 

 -- Qty: 100

 -- Price: 5.00

Actual Result: The Cost of Goods Sold for the 100 items sold is 45.00 (0.45 per item)

The costing method being used for Lot Numbered Items with multiple receipts is FIFO. Take note that the Cost of Goods Sold appears on the Invoice because the Item did not undergo the Fulfillment process. With Item Fulfillments using the Pick, Pack, Ship feature, the Cost of Goods Sold will be the Average Cost until the Item Fulfillment is marked as Shipped - when the Cost of Goods Sold will be recalculated using the FIFO Costing Method.