There should be an option to set different shipping charges region-wise.
Standard or common shipping charges for all shipments are not comfortable/justify in either sellers side or buyer side at all the time. Therefore, Sellers should have an ability to set different shipping charges according to the country, city or region.
(Eg. Shipping charges in Washington - 10 USD, in New York - 8 USD, to Japan - 15$, India - 17$). Then it would be more convenient to all parties.