I hope I remember this setting correctly, but in Apps 10:

If you want the same default tax code values for all suppliers, you can define tax codes for your site's delivery address(es) on the Company/Address/Tax Code tab.

If you want to specify different default tax codes for different suppliers, select the Use Supplier Address for Tax check box and enter the desired tax codes on the Supplier/Address/Delivery Tax Information tab .

Hi 

Thank you for your feedback

RazanR