I think you've just opened a very large can of worms again.
If I recall corrctly from the discussions some months ago, I believe the argument was that the arc-protection was required in bedrooms because appliances could be used in the room while somebody was sleeping (e.g. electric overblanket).
You'll find a lot of people here who don't go along with that, however.
Parallel-arc vs. series-arc debate resumes....