The EU VAT Assistant only checks for EU VAT numbers, it applies a VAT exemption on intra-EU sales.
EU regulations indicate that sales to extra-EU countries don’t attract VAT, therefore tax should not be applicable anyway if a shop in the Netherlands sells a product to a US customer. If you are required to apply VAT to extra-EU sales in some circumstances, and you need to distinguish extra-EU B2B transactions to apply a sales tax exemptions to them, most likely you will need to implement a customisation.
I would recommend to check your specific scenario with your accountant, before taking that route. Chances are that you might not have to apply sales tax to begin with, with extra-EU customers.
Important
Please note that the EU VAT Assistant, as well as our other plugins, don’t calculate taxes. Tax calculation is performed by WooCommerce, based on the rates you configure in WooCommerce > Settings > Tax.