At the moment, using the Multiple Emails technique for our custom/3rd-party Integration feature will just send the additional email address(es) a copy of the raw order data that we received in the IPN from PayPal, rather than adding a section above that duplicating the data in a more human-readable format. This is because we cannot anticipate whether the emails will be read by a human being or just by an automated script that handles raw IPN data (and would get confused by anything extra in the email).
We do have a wishlist item to add some way of specifying the format of Multiple Emails (e.g., perhaps an extra parameter you could add in the integration URL to add the human-readable section like Sale Notification emails have), so that may become a new feature eventually.
