Hi,
By changing a little your checkout workflow, the coupon code now works great.
I am still investigating on my local website without reproduce the bug. So I still looking at your configuration, looking for the option or the plugin which would made the difference.
But your coupon is working fine in your website
Regards,
Jerome - Obsidev.com
HikaMarket & HikaSerial developer / HikaShop core dev team.
Also helping the HikaShop support team when having some time or couldn't sleep.
By the way, do not send me private message, use the "contact us" form instead.