Hi Sandra Showalter,
You're doing the correct way to override the tax amount. However, we don't want to stay in that way. For that reason, I would recommend contacting our our phone agents. They can do a screen-sharing session to check to see your setup. Also, they'll be able to check if it's still possible to revert your interface to manual sales tax.
Here's how to get their number:
If you need anything else, feel free to get back here.