These new guidelines provide specific guidance about special symbols. The particular symbols that need to be on a list symbols list are given in the section that applies to them. That's why the math symbols used in spellers are given in the section on spellers.
The General Purpose Symbols are just that--a list of just about ALL the symbols used in braille. These do not necessarily go on the special symbols page. They include punctuation and composition signs. Would you put a comma on the special symbols page? A capital sign?
Look in the Index under Special symbols. You will see a list of the various sections that require special symbols, including Spellers. When working with material that applies to those sections, you'll see which symbols are needed for that material.