For document types on the "publication" end of the Document Type Spectrum it seems self-evident to assemble a document schema in "document order"
But for document types toward the "transactional" end of the spectrum there are likely to be a variety of different presentations for instances
Is the sequence of line items on a purchase order important? If you're buying a few books from amazon.com they probably aren't, but sometimes purchase orders are sequenced in "warehouse picking order" to make fulfillment more efficient