Let me try and explain again. There was no set rules in the standard "Classic" fly hooks meaning there were no specifications saying a 2X strong hook was XYZ in diameter in a size 12. It was a bit subjective. In the Signature range, because everything is proportional, all hooks are based on a set of master specifications for the entire range. So let me use some fictitious numbers in an attempt to explain.
Let's say a Classic hook in size 12 had a wire diameter of 0.65mm and was listed as a 2X strong. Well in the new Signature series that 0.65mm wire diameter for a size 12 is classified as a 3X strong. REMEMBER, these are arbitrary numbers for example sake only. So in the original Classic series it was called 2X strong but in the new range it falls under a 3X strong classification. Same goes for lengths. We didn't take a hook that was 2X strong and say, "Hey, let's bump up the wire diameter and then call it a 3X strong." That is just how the measurements converted over from the Classics.
Hope this helps to answer your question.