I'm not sure it matters about applying "prefer duplication over the wrong abstraction" at step 3 or step 6 nearly as much as applying that advice at some point.
I often consider "is this abstraction going to be prone to misuse" (regardless of if it's the second, third, fourth... copy) and try to head it off with either strict typing or comments or internal visibility - to try to do step 3 without opening up as big of a door to step 6, but the important thing is less when to do stuff like this but just to try to avoid things reaching step 7.
I often consider "is this abstraction going to be prone to misuse" (regardless of if it's the second, third, fourth... copy) and try to head it off with either strict typing or comments or internal visibility - to try to do step 3 without opening up as big of a door to step 6, but the important thing is less when to do stuff like this but just to try to avoid things reaching step 7.