Requirement: Not to associate LCM invoice to Trade Operation

My client has the requirement to capture item cost by the material cost in PO and Trade Operation estimate cost only. Any variance occurs during landed cost invoice creation should not impact the item cost; and the variance accounting should falls in COGS account instead of inventory valuation account.

However, the general landed cost process is to associate the landed cost invoice to Trade Operation. When there is variance in the actual landed cost v.s. estimate cost stated in Trade Operation, the difference is to be reallocated in the Trade Operation and then the corresponding cost adjustment transaction will occurs in Receipt Accounting.