Just as a side note, My API test kit was reading almost 5. DKH off, it could have been the kit, but the massive amount of complaints I found while researching on the web seem to defend the position that they can't be trusted.
I also used some of the Sailfert calibration fluid on the API and found that it gave me a different reading each of the 4 times I tried it, however both the lemontte kit (not included in your write up, but my personal favorite) and the sailfert came back with the same readings from the calibration fluid each time and they were both spot on.
I also used some of the Sailfert calibration fluid on the API and found that it gave me a different reading each of the 4 times I tried it, however both the lemontte kit (not included in your write up, but my personal favorite) and the sailfert came back with the same readings from the calibration fluid each time and they were both spot on.