I have multiple storefronts with Magento, and I want to limit the Integration to only use Avatax on certain stores, and use my tax calculation in other storefronts.
When in the Magento Admin Panel, select the Current Configuration Scope:
You should be able to chose the storefront's configuration.
Go to Tax, and disable Tax Calculation in the Action Pulldown.
Save the config.
By using or changing the Store's Configuration, it should override the Default Config.
Highlighted in Orange is where the storefront Configuration chooser is located: