Hi,
Nicolas has made a bug report for that option and we will perform some tests in order to fix the issue.
The option was added recently and we didn't have the time to check all cases (the point system have a lot of possibilities) and it looks like that some cases, like yours, had issues with it.
So we will reproduce your issue and understand more deeply in the code what happen exactly.
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.