I think it'll be a serious, serious error for this not to be SECTION_DATA. Maybe POST_DATA is OK, but even that seems like an implementation compromise not "the way it ought to be".
We'd have to split them on account of when the underlying object is created. Index statistics would be SECTION_POST_DATA, and everything else would be SECTION_DATA. Looking ahead, statistics data for extended statistics objects would also be POST. That's not a big change, but my first attempt at that resulted in a bunch of unrelated grants dumping in the wrong section.