Min price fails if product/category coupon

-- url of the page with the problem -- : maxmon.co.uk/buy/products
-- HikaShop version -- : 2.6.0
-- Joomla version -- : 3.4.5

I'm trying to offer a coupon which applies to a low-cost item (20m audio cable - £15) when purchased with a more expensive item (£310). I created a coupon with a min order value of £300, associated it with the low-cost product item, added both the expensive and inexpensive items to my basket and went to the checkout. When I try to add the coupon it complains "Notice: The voucher code you entered cannot be used in an order under £300.00" despite the more expensive item being over £300. Same issue if I associate the coupon with a category.

When I lower the coupon min order value to below the value of the inexpensive item it works. So it looks like when a coupon is associated with a product or category then the min order value is not of the total order (which I think is logical) but only of the to-be-discounted items?

Help!

I'm not totally convinced by that workaround, and I'm completely baffled now by what is intended by associating discounts with specific products or categories. Surely the min order value should refer to the total order value, not the discounted portion of an order?

Hi Nicolas:

I think HS must have some logic that says if the checkout includes a coupon associated with a product then the min order value must be greater than BOTH the coupon min order value AND the coupon-product price.

Test case:
- Product HICOST £300
- Product LOCOST £15
- Coupon TEST (min order value £200, associated with LOCOST)
- Add HICOST, LOCOST and coupon TEST to checkout => min value warning

I have to reduce coupon TEST min order value to <= £15 (i.e. the price of the associated LOCOST product) in order for the coupon to be accepted. This prevents what seems to be a very useful use case for coupons, namely to provide coupons for LOCOST items that can only be used when purchased in conjunction with HICOST items, i.e. buy something expensive, get something less expensive for free. This would seem to be enabled by removing the apparent constraint that the min order value must be >= the coupon-product price. Why is that constraint there? Min order value should just be min order value.

It's got to be a bug when you are looking at a basket with £385 of goods in it and see an error message saying 'Notice
The voucher code you entered cannot be used in an order under £300.00'. No?

Digging deeper ...
In administrator\components\com_hikashop\classes\discount.php: function check(&$coupon, &$total, $zones, &$products, $display_error = true) you check a coupon against the cart contents
Towards the bottom of the function you assemble a list of products (in $coupon->products) that match the products or categories associated with the coupon (or all the products in the cart if there is no product or category restriction). This list is used to sum up the value of the order for comparison with $coupon->discount_minimum_order.
IMO that's a bug. The min order value compared should be that of ALL the products in the cart, not just the products associated with a coupon category or product restriction. What is the rationale/benefit for the current behaviour?

Thanks for prompt responses but I'm not really convinced. I think the HS coupon system has become unintuitive and could do with an overhaul. Adding a plugin doesn't seem too hard, but I think I'll investigate simpler workarounds like custom fields first. I'm not sure I like the idea of adding a paid third tier (Joomla - HS - AWO) just for this.