Buy-In Badinage

Often one or more of the signatories on a rabbinical epistle, or book or organization approbation, adds his own two cents to the basic text, before adding his signature. Except the added paragraph adds nothing significant whatsoever! The textbook-style texts are dull as dishwater without making them even longer!
It’s not like those signatories read the text any more (or less) carefully, or personally had anything extra to do with the subject matter. You can refute these theories by browsing through Kraina De’igressa or Michtavim Uma’amarim or glancing at the latest street pronouncement.
Rabbi Elyashiv, for instance, would write “ג”א מצטרף”. Was he trying to give the letter a round-robin character?
It’s like those stuck-up restaurant patrons requesting the chef prepare them their own favorite dish; one missing from the general menu…