Why did Hurst abandon cmaps? They are the best tool for forecasting turning points that I have ever seen by far. The trick is in understanding where to point the projection. That comes with experience. You get a feel for it. If you do it for awhile, you will get the knack.
I never bothered with the last chapter and the addenda. That stuff is purely for rocket scientists. It's not needed. I wonder what I could have done with that kind of training. Woulda been fun. But there's more to it than just number crunching.
I'm not Hurst so I don't know.
The later Hurst stuff uses VTL's (Valid Trend Lines) and FLD's (Future Lines of Demarcation), and counting the cycle bottoms. I don't know whether it was because he found these methods to work better, or whether they are just simpler to do with pencil and paper (remember it was the early 70's), or both. The methods are related to each other mathematically, so I would expect that they produce similar results.
IMO, the last chapter and appendix of Profit Magic is the most interesting part, albeit probably the least useful for actually making money. I am an electrical engineer in real life, so many of the concepts were already familiar to me.
Also, there is much more to being a successful trader than understanding Hurst theory (as I have learned the hard way). One thing that is apparent from reading the "Cycles Course" is that Hurst was extraordinarily methodical and disciplined.