The dot should not be visible. That is what disappeared means. Taylor has a video on their website that illustrates this. Click the pool/spa link on the upper right and scroll down for the CYA testing video for the K-2005 or K-2006. They are the same. As you can see in the video the black not is not visible at all.

The pool store test is not to be trusted. I used to work in one and know how people tend to test water. It is done fast to maximize the bottom line. Your own testing is going to be better if you just follow the directions and take your time. You can always pour the contents of the view tube back into the dispensing vial and add it back into the view tube to see if you get the same results.