Greek treats the noun (τὸ) ὑπερβατόν (grammatical term) as oxytone, with persistent accent on the ultima. In the adjective ὑπερβατός, the accent follows the usual rule and reverts to the antepenult in compounds (ἀνυπέρβατος, εὐυπέρβατος). Sometimes later ecclesiastical writers make the adjective ὑπερβατος proparoxytone, e.g. ἡ ὑπέρβατος ἡμέρα (Passover). The proper name Hyperbatus is always proparoxytone. I see that a number of modern writers misplace the accent on the noun ὑπερβατόν, especially on the Misinformation Superhighway.