Stupid question but how do you know the KHG is wrong and not the Hana?
Agreed, I would get a third and fourth reading to verify, grab a salifert kit or even a cheap API kit, maybe take a sample to LFS and have them test. When I was setting up my unit it was about 1dkh off from my salifert kit, but that kit only had a few tests left, opened a new kit and the KHG was only a few tenths off that kit.