I just received books as part of a 3 for 1, and realized that the books that were not the one that I had requested had lost all their PBS history (if they even had any) because they were not traceable through the pbs system.  There should be a way for a book to retain it's history and be part of a deal.  An option to attach a book on my bookshelf to a request that has already been made could be one option, or - when you go to 'request additional books from this member'  there could be an option to select as 'for credit' or  'deal',  and each member could have control of how many 'deal' books can be attached to one request.    This way there could be traceability not only on a book's passport, but also on how many books are actually moving through the system.    Anyone know if this had ever been used by PBS or if it might be in the works?  I am relatively new here myself.

You could order all the books that you want from the member's shelf, then they could buddy back the extra credits.  I did that with someone - I ordered 10 books in a 10 for 4 deal and he buddied 6 credits back to me.  The books I received kept their history, plus I knew that the 10 books I wanted had been removed from his shelf.

There is an option from the other direction.  The sender can select send a book to a friend.  This would not record what you ordered.  But the book stays in the PBS system and keeps the passport.  This does not involve credits.  I warn you that you have to have the address before you select this option.  (Print out the credit book without postage first, then select the freebies, then reprint the credit book with the corrected postage.)