Sales tax miscalculations

I’ve just set up the WooCommerce Shipping & Tax plugin, and enabled automated taxes. At checkout, I now see a sales tax amount added to the final purchase price. But the amounts are off, not by a lot, it really would bother me to know I am overcharging my customers on sales tax, even if it’s just a few cents.

For example, on a $14.95 purchase, WC added a sales tax amount of $1.37. The current tax rate for the postal code the order was placed from is 7.2%, so the amount of sales tax for this order should be $1.08.

Exactly what are these automated tax calculations based on? Where are you getting the tax rates you’re using? Do I have any access to view/edit them? Is there any possibility of correcting them? If not, then I guess I’ll just have to manually enter all the tax rates for every zip code and manually maintain them.

I’m hopeful I can make the auto feature work — any helpful insights anyone can offer would be greatly appreciated.