Thanks for your suggestion, pghaworth. As I mentioned in my original post, since I am outside the whispernet network, I have downloaded all my amazon purchases onto my computer for transference to my DX — via calibre wherein I changed the metadata to my preferences (such as adding a #_ to the title so I could tell at a glance the order in which a series of books was written; and to correct for those books alphabetized by first, rather than last, name). Your first response triggered a vague recollection I had picked up on the kindle discussion forum regarding the necessity of downloading each purchase to a specific device. To this end I spent quite some time this morning in "Manage Your Kindle" sending all 440 books specifically to my Kindle 3 (which, being new, is equipped with International Wireless). All the books arrived "safely" and I thought my problems were over.
I then made sure "kindle 3" was selected as my calibre device and then connected my K3. I highlighted all the titles which calibre indicated were not yet on the my K3 and then hit "send to device" — which is EXACTLY the same procedure I use when downloading to my DX, and I have is no difficulty in transferring these "improved" metadata to this kindle.
After I sent all my books specifically to my K3 via whispernet, I now have two versions of those books for which I changed the metadata on calibre. For example, the e-book title of a mystery by Lee Harris is "Murder in Greenwich Village: A Manhattan Mystery," which I changed via calibre to "Murder in Greenwich Village (#3). Also I corrected the metadata so a book by Alexa Adams would be listed under "Adams," rather than "Alexa." These corrections have all been successfully transferred from calibre to my DX but, for some inexplicable reason, I am unable to do so with my K3.
I have tried all the options I can think of to "make it right" but, alas, to no avail. Guess my next step is to pose the same question on the kindle forum. Perhaps someone there has had the same problem and found a solution they would share with me. It seems a minor thing to get my knickers all in a twist about, but being thwarted like this just activates my OCD genes and makes me more determined to resolve this molehill I have made into a mountain!