Julie I have thought the same thing but for a different reason. Because books can languish from submission to final approval for a long long time, and because some books just might not make the collection due to technical reasons such as unverifiable copyright, volunteers who truly want a certain book have an incentive to grab it from step 1. If they imediately release back the book to Step 1, no harm is done. If, however, they retrieve a book and do not release, a week is lost.