Wihtout a doubt..it is a lot of speculation. But I have not been able to find anything that makes sense. I actually sent my purchase back in and got one back with exactly the same issues.. I dont want to chase numbers either..but I would be comfortable with consistency. I guess accuracy is just a bonus?That is a lot of speculation.
I have heard of a few bottles of calibration being reported as bad but nothing related to the unit on its own. Not that I would know about it as I don't work there. On the other hand I did preform the self service and that wasn't a part of the service package / kit.
The reason why some say don't chase numbers is because it will lead you to pull your hair out. They are different methods and different accuracy levels. Hanna HI755 ALK is +- 5 ppm for example.
Regarding precision...see below. I call this exhibit 1. If you can't hit this precision and accuracy, you should not be advertising with it.