The recipe indexes are identical because the editions are linked on EYB. We only index one edition then link all others if the content is identical, so the index, member notes, ratings and recipe photos are shared across all editions. If a new edition is revised or expanded we copy over the index and make the necessary changes.
You can tell if the book is a linked one in a few ways. If your edition is linked you will see a links icon at the top after the book title. If you hover over the link a pop-up tells you which is the indexed edition. You can also view all linked editions to the indexed edition by clicking the links icon on that edition listing or view the More details tab on the Book details page where all the linked editions are listed. Here is that page for Pride & Pudding.