I ran into an issue with the plugin and found this old thread.
https://wpfactory.com/support/topic/preserve-base-country-not-working/
However after testing this myself i found out that it isnt correctly working.
We have B2B customers that order on the shop for other offices within the EU.
So for instance if a German B2B customer is ordering with a valid VAT no but adds a a different delivery address, the VAT could have 2 options.
Option 1, German b2b customer is ordering and delivering this to another EU country (not base country), VAT should be ZERO.
Option 2, German b2b cutomer is ordering with a valid VAT no and delivering to base country, in this case VAT should be added.
However with the current options (Check for matching billing country code and Preserve VAT if shipping country is different from billing country) i dont get correct results.
For instance, i entered a German customer who wants to deliver to the same country as where the shop is based, it is correctly adding 21% VAT (Netherlands).
But if a German customer does the same but enters Italy it also adds 21% VAT which isnt correct. It should add zero VAT.
Am i configuring this wrong or is this not supported right now? The shipping country is always leading in terms of taxes so this should be configurable with the plugin.
A simple option is to add an option like preserve VAT calculation for base shipping country. This would help to fix this issue.