Hi there @JD1 and @CCIlumia, we created a Hubspot integration that might solve your tax calculation issues. We built it to do quoting/invoicing and payments and are happy with the functionality. If you’d like to check us out, we have a no card required 2 week free trial. I’d love to get your feedback.
This is the Hubspot integration page: HubSpot Marketplace
Here’s our site: https://paycove.io/hubspot-invoicing-integration
Thanks and let me know if you have any questions!