Can I override tax logic in Advance Tax to NOT require tax codes?

One of our customer records in the US can sell to Canada shipping addresses.

However, due to other setup I’ve just completed for other customers in Canada, NetSuite is now looking at our US-based customer orders with customer shipping to Canada (ON specifically) and requiring Canada line item tax codes when invoiced.

Note: we are using Advanced Tax, not SuiteTax.

I realize this behavior is by design. Ideally, I’d like to “short circuit” the logic for tax code lookup to make it ignore the fact the customer shipping address is in Canada, and treat the US-based customer sales as non-taxed. The US store customer record is set non-taxable and has no tax code item.