Freight terms on PO do not match freight terms on the supplier site

I have assigned an item to a specific supplier site but when the purchase order is created from the DRP or Min/Max the Freight terms do not match what is set up on the supplier site or on the quote that the item is referencing.  My goal is to have some items purchased from this supplier automatically ordered by airfreight, hence the separate site and freight terms.  Does anyone have any ideas on how to correct the issue?  Thank you.

Ashley