Transaction OMW1 allows you to set whether the Price Control is a mandatory "S" or "V".

V indicate that you want the system to value the stocks with the latest price.
S indicate that you want the system to value the stocks with a fixed price method.

Price Control V - Moving Average Price

Assume Material Master current price is 10

Goods Receipts for Purchase Order - Movement Type 101

• Material Document Posting created - inventory increases
• Accounting Document Posting created
• Debit      12345   Inventory      12
• Credit     67890   GR/IR          12
• New Moving Average Price = ( GR value + Total value ) / ( GR quantity + Total stock )

Invoice Recipts for Purchase Order - MR01

• Accounting Document Posting created
• Debit      67890    GR/IR          12
• Debit      12345    Inventory     3
• Credit     45678   Vendor        15
• New Moving Average Price = ( Inventory difference of 2 + Total value ) / ( Total Stock)

Price Control S - Standard Price

Material and Accounting Document is the same.
The one with the lower value will be posted with a price variance entry.

Goods Receipts for Purchase Order - Movement Type 101

• Material Document Posting created - inventory increases
• Accounting Document Posting created
• Debit      12345   Inventory           10
• Debit      23456   Price Variance   2
• Credit     67890   GR/IR               12
• No change in Standard Price

Invoice Recipts for Purchase Order - MR01

• Accounting Document Posting created
• Debit      67890    GR/IR                 12
• Debit      23456   Price Variance     3
• Credit     45678   Vendor                15
• No change in Standard Price

General Ledger Account Configuration
Transaction OMWB - Automatic posting for inventory
Inventory posting                                     BSX
Goods receipt/inv.receipt clearing acct     WRX
Cost (price) differences                            PRD
Transaction XK03 - Account Payable Vendor Master
Tick Accounting info. and hit the Enter key
Field name    Reconcil.acct     45678