FedEx: NetSuite still calculates shipping cost using the Negotiated rate even if the FedEx Rates Type is already set to List Rates for International shipments

For International shipments, NetSuite always uses the Negotiated Rates that the customer have with FedEx. 

The preference under Setup > Accounting > Shipping > Preferences tab for FedEx Rates Type is only applicable to Domestic shipments.

This information can also be found on the field level help if you click the FedEx Rates Type field.