I cannot get the front end to display taxes per zip code. I am based here in OK and I want to make sure that only OK residents are being charged sales tax. Now that being said the tax rate fluctuates quite a bit in the state so I thought the best idea was for me to get a CSV with all the different zip codes and they're subsequent tax rates and import that (in Magento format) into the "tax zones and rates". I imported and it worked flawlessly they are all now in there. So I go to tax rule assign retail customer tax class, product tax class as taxable goods, and selected ALL of my zip codes (using the zips as IDs as well). THIS ISSUE IS NOW everytime I go to my store it always calculates ONLY on the last zip code. What can I do to fix this issue ??