FIFO Costing Problem

Dear friends,

I'm David I have an excel which can calculate FIFO costing base on Items ID.
But unfortunately, It has some error that i can't solve it.

Below is the objective that I'm attempting to do.
I have two sheets, The first is Stock-In and the second one is Stock-Out.
The sheet Stock-In record all of goods that i purchased. Stock-Out record items that i withdraw out and whenever i insert item, quantity
Excel will calculate Cost value automatically and it also will refresh calculation at next the time if i make changing.

Here is the list of the two sheets:

Stock-In
Date Item Qty Price Value

01-Jan ItemA 10 5 50
02-Jan ItemA 15 7 105
03-Jan ItemB 5 10 50
03-Jan ItemA 4 8 32

Stock-Out
Date Item Qty SalePrice SalesValue CostValue
04-Jan ItemA 5 6 30 25
05-Jan ItemA 21 7 70 138

My problem is that in the Stock-Out sheet on 05-Jan when i withdraw ItemA from 1 to 20 of Qty the Excel calculate FIFO costing is correct but
when I try to increase up to 21 items the Excel calculate wrong FIFO costing.

Thus, Do you have any ideas with this?

Note: I attached my sheet with this Thread as well as highlight the issue on Stock-Out sheet.

Thank in advance for sharing your ideas.

DAVID

The code that i attempt to connect is:

Private Sub Worksheet_Change(ByVal Target As Range)
Call FIFO
End sub

David,