At softlogs we put in all suppliers with associated alias names. In this way we can link purchase orders to both freight costs and customs costs and based on that do landed cost analysis. The supplier can easily upload / send in trade invoices and related documentation to make the customs process easier and to rationalize expensive intermediaries with arrival notifications and other document fees.
All cost are linked together and can be paired against each purchase so that you have complete control and overview of the landed cost both on purchase orders and at the product group level.
Reports and KPI´s available in tonnes / km or freight share by item value are reports that are available directly from the system. This way you can see if you are working with the right markup for each supplier.