Issues with tax calculations and coupons

[jeremyk]

We are currently implementing AC 7.0 and have noticed a fundamental issue with tax calculation and coupons. AC calculates the tax before applying the coupon which is incorrect. For example, if the order is $100 and coupon is 10% and tax rate is 7%, in AC it calculates tax as $100 x 7% = 7$ however we need to calculate it ($100 - $10) x 7% = 6.3. Has anyone else noticed this issue?

[jmestep]

I don't know if it's "incorrect". In some states, you have to pay tax on the amount before a coupon. So it would have to be coded for both options and the merchant would have to select which option for which state.