Changes in Material Valuation 
Use
There are two types of changes in Material Valuation:
Automatic changes
Manual changes
Features
Automatic Changes
Changes in Material Valuation due to goods receipts and invoice receipts are carried out automatically when the relevant transaction is posted.
The extent to which the stock value changes depends on the sequence in which the goods receipts and invoice receipts are posted. The SAP System allows for both possibilities:
When goods are received before the invoice, the stipulations in the purchase order are used as the basis for posting.
When the invoice is received before the goods, the details on the invoice are used as the basis for posting.
Manual Changes
You can change the valuation manually. The following changes are possible:
Revaluation of a material due to:
A price change
If the material price no longer corresponds to the current market price, you can adjust it by making a price change.
A material debit or credit
If the stock value of a material is to be increased or decreased, you can make a direct credit or debit posting for this material.
Posting of physical inventory differences
If a physical inventory reveals differences in quantity between the physical stocks and the book inventory, you must correct the book inventory balance manually, that is, the physical inventory differences must be posted. Adjusting the stock quantity leads to a change in the value of the stock.
See also:
Value Changes in Inventory Management
Value Changes in Logistics Invoice Verification