Hi..
This cause is Stock Shortage at Order Settlement when to use the Moving Average Price.
Ten piece of material FERT was produced in Jan period and delivered to stock at a price of $100.
Dr) Stock 1000 Cr) Clearing account 1000
Five pieces were sold to customer in Feb period
Dr) COGS 500 Cr) Stock 500
There is 10 piece left in material stock at period end(Jan period) but 5 piece left in material stock at Feb period. A variance of $10 is calculated for the production order.
The below FI document will be generated through settlement job.
=> Posting date : 2014-01-031
Dr) Stock 10 Cr) Clearing account 10
=> Postingdate : 2014-02-01
Dr) Price difference account(UMB) 5 Cr) Stock 5
Refe to sap help site : Valuation with the Moving Average Price - Actual Costing/Material Ledger (CO-PC-ACT) - SAP Library