Coupon takes off double the percentage

-- url of the page with the problem -- : exo-l.com
-- HikaShop version -- : 1.6
-- Joomla version -- : 2.5
-- PHP version -- : 5.3.13
-- Browser(s) name and version -- : Firefox (latest)

I don't know when this issue started, my client just told me about it. But for some reason when I enter a coupon code for 5 percent off, it will take off 10%. What is going on?

I add 1 product, enter the discount and all of a sudden, bam, double the percentage. Test it yourself:
Code:
go exo-l.com/nl/webshop . Click "in winkelmandje", close the modal and press "Kassa"

There you can enter the discount code. I have it set to these settings:


I'm a php developer so I don't mind looking through the code if I know where to start looking

Hi,

Probably a bug in administrator/components/com_hikashop/classes/discount.php
It's also probably already fixed in recent versions of HikaShop, so updating would probably fix the problem.
However, I would recommend to do an update test on a copy of the website and a backup before updating as you have quite an old version of HikaShop