Dear Mr. Khaled
I assume you have received inventory items with incorrect cost which need to be adjusted. This can be done from the "Inventory Adjust Costs" window:
Microsoft Dynamics GP > Tools > Utilities > Inventory > Adjust Cost.
Through this window, you pick the item, then a specific cost layer, change the cost and then process. This window ensures that the cost adjustment will be made in Inventory through GL.
In your case, you have received the first item with the incorrect cost .066 , when adjusting cost, the distribution will be reversed to increase the inventory account and decrease the offset account. You can calculate the number as follows;
Unit cost Variance (0.66 - 0.066 = 0.594) * Transaction Quantity (30000 ) = 17820
Best Regards,
Mahmoud AlSaadi