Hi bills-aplus-outl,
Welcome to Community! QuickBooks Online Sales tax feature, has everything you need to add, apply and record sales tax, keeping aligned with government guidelines. I can see how applying a group rate to previous transactions would be beneficial. However, at this time, the option is currently unavailable. Although you can create a new tax rate, it will be applied to your transactions moving forward. Previous transactions will need to be edited manually.
If this is an option you would like to see in product updates and feature enhancements, feel free to submit a suggestion to our Development Team. Customer recommendations are greatly appreciated in assisting with improving your overall experience with QuickBooks Online.
Please don't hesitate to reach back out, if you have other questions. We'd be happy to help!
