Different way of calculation

Hi there. I just love this plugin . It is very simple to use and not complicated. but i have a question . As the title is saying i can see the plugin is dependent on all address fields. Now i am using it for a store based in Romania and here google maps is not “knowing” all streets for example. And of course the plugin then is not showing the cost of delivery as he do not have all the fields detected.
But it will be great that if somehow the plugin can be triggered only on 4 fields wich 99% time in this country is enough…For example Country-County-Town-Zipcode. As for now for example if you don#t insert the apartment field the plugin will not work.
If there is anyway possible let me know.
Regards