I did realize that for Texas, if the rate is listed at 10%, I could just change it to be 80% of the rate, which would be 8% instead - it would still be 'taxing the entire amount' just at a lower rate but should work out to be the same tax amount overall

also this: https://help.avalara.com/Frequently_Asked_Questions/NetSuite_-_Knowledge_Base/Why_is_the_tax_rate_showing_in_NetSuite_off%3F

@Nick W. that's interesting, sounds somewhat similar

I'm guessing this Texas rule is only on certain classes of goods or services (perhaps only services, given this is a services company) -- in theory that would imply a different tax schedule on those items, but NS tax schedules only let you configure nexuses to be on/off, not different rules - sounding like a 3rd party is the only true option, beyond simply reducing the tax code rates manually by 80% after downloading - this also assumes that all subsidiaries operating in this nexus would behave the same way, which doesn't sound like a safe assumption

but if it is only for specific items, that may be another story. For our purpose we use Entity Codes for shipping addresses in AvaTax for all sales by these customers.