Use case - Landed Cost Billed Separately With a Cost Estimate

1-Enter Inbound Shipment with landed cost 

Category:Freight

Amount: usd 50

2-Enter Item receipt

3-Enter Vendor bill with item Freight with the same expense account, select Category Freight and enter amount usd 60

4-Edit Item receipt to change source to Other Transaction but this field is greyed because Landed Cost per line is checked

But we can not change this field because item receipt is generated by background process of NetSuite from inbound shipment

So, how we resolve this use case in NetSuite?

Thanks

Regards

Carina