Sometimes referred to as a costing packet, Jim2 allows applying (link) positive and negative value expense orders to specific purchase orders to affect the landed cost of goods. Similarly, in a Multi-Currency environment. Expense orders in any currency can be linked to purchase orders in any currency.
Linked expenses would include billing for things like freight, insurance and duty that are received separately to the purchase, but really should be reflected in the landed cost of goods.
In Tools > Options > Accounting set the preference for expense posting date
Further information