Is there a way to add import charges, to see if they are really loss making with these additional costs.

planning wise this a bit harder, the planning tool does not take that into account that information i do not know on that page.

Your best friend then is this page (this is the page i use most often to see if i'm resource positive overval):
https://land.spl-stats.com/player-overview/overview

This takes into account the transfer fee when you have a negative in a certain region.

Here you see there is a 10% added to the grain to cover the transfer fee if you get it from other regions