Interesting difference in how coupons are applied in combination with taxes

-- HikaShop version -- : 2.6.4
-- Joomla version -- : 3.6.5

We've been doing some testing of different coupon options and their effect on taxes, and found something curious. We're wondering if it's this way on purpose or if it's a bug (or undocumented "feature", lol)

If you leave everything the same in our settings and our coupons (which are overall coupons, not product specific) and we ONLY change the type of coupon from a % off coupon to a flat rate ($ amount off), how the coupon is applied to the products for taxable and non-taxable items is very different. Let's pretend the tax rate is 7%

Let's say we have 2 items in our cart.
- A taxable item for $300
- A non-taxable item for $110
Total in cart = $410

If we use a coupon for 25% off, taxes are applied to the following net prices:
- Taxable item = $300 - 25% off = $225. With a tax rate of 7%, this = $15.75 in taxes
- Non taxable item = $110 - 25% off = $82.50 non-taxable

If we use a coupon for the same amount but as a flat rate of $102.50 off, taxes are applied this way:
- Taxable item = $300 - $197.50 = $. With a tax rate of 7%, this = $13.83 in taxes
- Non taxable item remains $110 (the entire flat rate coupon gets applied preferentially to the taxed item first)

While I can see the benefit to the customer of reducing their taxable item(s) first to save them money, technically this is not correct (when the coupon is "overall" and not for the taxed item(s) only)

The amount of a flat rate coupon should instead be applied proportionately, like this:
- The Taxable item is 73.17% of the total order value. So the coupon should be applied as $300 - ($102.50 X 73.17%) = $300 -$75 off = $225 x 7% tax = $15.75 in taxes
- The non-taxable item represents 26.83% of the total order value. So the remaining coupon amount should be applied to this item.

As you can see, the way HikaShop is applying taxes for flat rate coupons is artificially reducing the taxes collected by applying the full value of the coupon against the taxable item(s) first. Technically this is incorrect (at least in the states!) and could lead to the store owner being audited and responsible for paying the difference of the uncollected taxes.

Is HikaShop doing this on purpose, or is this a bug?

Hi, Nicolas I am in the exact same situation. I have a cart that has quite a bit of modifications on version 2.6.4 and some 3rd party extensions that are not quite ready for version 3 of the cart. Is there a way to get a patch to fix these tax issues on version 2.6.4? I know I need to upgrade to version 3.0.1 however, the client is going to have a large sale starting in May and the tax is calculating incorrectly and it is currently impossible to upgrade the cart to version 3.0.1 because it would take to long to do this.


Thanks,

Josh