I worked a little on module improvement. I corrected some things that didn't worked for me like wrong weight calculation, wrong max amount calculation.

I will be able to post the modification for test, but there is still a bug.

You cannot get the worldquote shipping cos when you create the order in the administration page. Did the module bug like that on your installation ? I tried the modified module I did and the original module, and the bug appear on both installation. I don't know if it's my drupal installation that make it don't work or if it's a real bug.

Can you bring feedback about this feature, I will try to correct it if it's a real bug and post the improved module.