There are two ways your specified "Tax Rates" can be calculated within your transactions.
Your Tax option will be default set as a "Post-Tax" calculation. Meaning that the rates will be added to the Final Subtotal, after calculation, there will be a new Final Total.
The Pre-Tax option will still calculate a value based on the specific rates, but NOT affect the Final subtotal. With this option enabled, Blaze we reverse engineer the applicable tax rates starting from the Final Total.
It is important to keep in mind the order/sequence the rates are calculated will start at the top and finish at the bottom. City > County > State > Federal. (If the "tax option" is set to "complex").
Always run a test transaction to test your tax rates, to ensure you are getting the calculations you want.