Take a look in the knife making sections for its heat treating information. We have a separate section for blades because of the thickness issues, as well as the unusual steels used in knifemaking,
I also agree that your chart is for 1/4 inch thick (6mm) as it states itself on the graph. The other numbers at the bottom are depth removed after heat treatment showing how far they are ground down, which is showing the depth of the decarb layer.
Perhaps this is a language thing causing confusion. I lived in Germany in 1978 and made many errors due to language myself so I can understand. Also knowing English has many regional differences only adds to confusion.