What's the difference between expostulation and expostulatory?

Expostulation

Definition:

(n.) The act of expostulating or reasoning with a person in opposition to some impropriety of conduct; remonstrance; earnest and kindly protest; dissuasion.

Example Sentences:

(1) This behavior and other facts regarding double Soret spectra can be explained by a simple expostulation involving lipophilic and corrdinate binding of pi-acceptor ligands.
(2) Updated at 5.49pm GMT 3.26pm GMT During the session, The Times's correspondent Juliet Samuel tweeted a couple of highlights that I didn't manage to get into the blog: Juliet Samuel (@CitySamuel) V surprising Goldman admit they don't even look up what institutions actually pay vs what they claim they'd pay in negotiations #royalmail November 20, 2013 Juliet Samuel (@CitySamuel) Nadhim Zahawi love-in with bankers as he expostulates that #royalmail price will take "a long time to settle".
(3) Sad: what makes Donald Trump happy A close cousin to “Bad!” (qv) , “Sad!” is probably the favourite among admirers of the president’s climactic expostulations, because it encapsulates perfectly his weirdly emotional, bullying style.
(4) (1969), a dully temporising Hollywood account of the life of Che Guevara, in which at one point Sharif’s Guevara is confronted by Jack Palance ’s Fidel Castro with the mumbled expostulation: “Che, sometimes I just don’t understand you.” The Last Valley (1971) and The Horsemen (1971) were poorly rated would-be spectacles.