And that labeling would be important to emphasize IF we saw that Epicurus himself in his letters, or Lucretius in his poem, or Diogenes of Oinoanda on his wall were insisting on that labeling as a clear point. Nikolsky and Gosling and Taylor says we don't see that, and that Lucretius and Epicurus and Diogenes of Oinoanda are all using the word "pleasure" as the best term to describe tightly integrated word referring to all possible types of pleasure.
As I see it the best argument that Epicurus did insist on that labeling is the list of articles that Diogenes Laertius cites. However contrary to that argument is Nikolsky's observation that Diogenes Laertius was writing as a cataloger who (just like we may be doing today) was looking at Epicurus with the expectation to apply these labels to Epicurus' framework - a framework that does not necessarily turn on "motion" at all.
Diogenes Laertius is *citing* Epicurus himself when the term katastematic is quoted! (With editing added)
[136] Διαφέρεται δὲ πρὸς τοὺς Κυρηναϊκοὺς περὶ τῆς ἡδονῆς: οἱ μὲν γὰρ τὴν καταστηματικὴν οὐκ ἐγκρίνουσι, μόνην δὲ τὴν ἐν κινήσει: ὁ δὲ ἀμφοτέραν : : ψυχῆς καὶ σώματος, ὥς φησιν ἐν τῷ Περὶ αἱρέσεως καὶ φυγῆς καὶ ἐν τῷ Περὶ τέλους καὶ ἐν τῷ πρώτῳ Περὶ βίων καὶ ἐν τῇ πρὸς τοὺς ἐν Μυτιλήνῃ φιλοσόφους ἐπιστολῇ. ὁμοίως δὲ καὶ Διογένης ἐν τῇ ἑπτακαιδεκάτῃ τῶν Ἐπιλέκτων καὶ Μητρόδωρος ἐν τῷ Τιμοκράτει λέγουσιν οὕτω: νοουμένης δὲ ἡδονῆς τῆς τε κατὰ κίνησιν καὶ τῆς καταστηματικῆς. ὁ δ᾽ Ἐπίκουρος ἐν τῷ Περὶ αἱρέσεων οὕτω λέγει: "ἡ μὲν γὰρ ἀταραξία καὶ ἀπονία καταστηματικαί εἰσιν ἡδοναί: ἡ δὲ χαρὰ καὶ ἡ εὐφροσύνη κατὰ κίνησιν ἐνεργείᾳ βλέπονται."
[136] [Epicurus] differs from the Cyrenaics with regard to pleasure. They do not include under the term the pleasure which is a state of rest (καταστηματικὴν katastematiken), but only that which consists in motion (ἐν κινήσει en kinesei). Epicurus admits both ; also pleasure of mind as well as of body (ψυχῆς καὶ σώματος), as [Epicurus] states:
- in [Epicurus'] work On Choice and Avoidance
- and in [Epicurus'] On the Ethical End,
- and in [Epicurus'] first book of his work On Human Life
- and in [Epicurus'] epistle to his philosopher friends in Mytilene.
- So also Diogenes in the seventeenth book of his Epilecta,
- and Metrodorus in his Timocrates, whose actual words are : "Thus pleasure being conceived both as that species which consists in motion and that which is a state of rest."
- The words of Epicurus in his work On Choice [and Avoidance] are : "Peace of mind and freedom from pain are pleasures which imply a state of rest ; joy and delight are seen to consist in motion and activity."