2dads,
i agree that it is not a difficult concept to grasp. defining the concept might be the problem.
despite your confidence, the design protected airspace for lateral tracking is not based on +/- 5 degrees at all, so they are not the same thing. but i know that aip says i can't descend below a step or whatever unless i am within that tolerance. so i know what that rule is.
my question was where is the aip reference that makes your quoted figures a rule? and don't procedure designers use a 1:7 rule to clear obstacles after stepdown fixes?