choshen mishpat civil law - Why isn't maakeh in the Tur?

The chapters in Shulchan Aruch generally follows those in Tur, with a couple of exceptions here and there. One of those exceptions is that SA adds a final chapter, 427, to Choshen Mishpat discuss the rules of maake (a required railing around a high walking surface). Indeed, Tur doesn't discuss maake at all, so far as I can tell. This, despite its general coverage of all laws practically applicable nowadays in chutz laaretz. Why not?

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I see that dinonline.org discusses this question and mentions two answers but rejects them both as unsatisfactory:

1. A Rabbi Mazuz (I don't know which one, R. Matzliach or R. Meir, or perhaps another) suggests that the Tur's author wanted specifically 426 chapters. (The Web page cites this from Or Chadash 5755, chapter 145, which may explain why the author may have wanted 426 chapters. I didn't check.) But the Web page rejects that as insufficient reason to omit an important set of rules.



2. Another possibility is along the lines of the Tora T'mima's statement (which the Web page cites to D'varim 28, though I haven't checked it) that maake applies only in Israel because only there are roofs flat. The Web page rejects this also as incorrect: flat roofs exist elsewhere.

So I seek alternative explanations (or good defenses of the above explanations).