Bookworm, perhaps the difficulty is in the meaning of words, rather than the calculation technicalities. In other words, in EU-OPS "english", they use "default" when they mean "nominal".
I haven't read the original, just replying to your quoted text - but I would ask, "Why 3 deg "increasing in steps"? Specific approaches, especially NPAs, can be much less than 3 deg (e.g. Wick VOR 2.5 deg).