Coupon discount applied is incorrect

-- url of the page with the problem -- : www.kettlercise.com/checkout/product/cid-363
-- HikaShop version -- : 2.0.0
-- Joomla version -- : 2.5.11

Hi,
I have a strange discount being applied on the cart when using a certain coupon.
The link above is a link to a product page, there is a 10% discount coupon that applies to the category this product is in 'FB10' :

Scenario 1
Add to the cart:
Flavour = Raspberry Dream - Liberate Drink Shaker = No Thanks x 1
The 10% discount is applied correctly, £2.30

Scenario 2
Add to the cart
Flavour = Raspberry Dream - Liberate Drink Shaker = No Thanks x 1
Flavour = Melon Refresher - Liberate Drink Shaker = No Thanks x 1
The 10% discount is not applied correctly, the discount is £6.90.
The discount is taking 10% of product 1 (£2.299), 20% of product 2 (£4.598).

Scenario 3
Add to the cart
Flavour = Raspberry Dream - Liberate Drink Shaker = No Thanks x 1
Flavour = Melon Refresher - Liberate Drink Shaker = No Thanks x 1
Flavour = Vanilla Cream - Liberate Drink Shaker = No Thanks x 1
The 10% discount is not applied correctly, the discount is £11.49.
The discount is taking 10% of product 1 (£2.299), 20% of product 2 (£4.598) and 20% of product 3(£4.598).

Is this something wrong with the configuration of the coupon?

If this has been fixed in a later version of Hikashop is there a way to fix this with a patch instead of me updating Hikashop as customisation has been done.

I have attached a screenshot of the coupon configuration

Hi,
Firstly can you download the last Hikashop version through our website, install it and test it again ?