24 Elders Cast Their Crowns? (Revelation 4:10)

πεσοῦνται οἱ εἴκοσι τέσσαρες πρεσβύτεροι ἐνώπιον τοῦ καθημένου ἐπὶ τοῦ θρόνου, καὶ προσκυνήσουσιν τῷ ζῶντι εἰς τοὺς αἰῶνας τῶν αἰώνων, καὶ βαλοῦσιν τοὺς στεφάνους αὐτῶν ἐνώπιον τοῦ θρόνου, λέγοντες (WH)

πεσοῦνται οἱ εἴκοσι τέσσαρες πρεσβύτεροι ἐνώπιον τοῦ καθημένου ἐπὶ τοῦ θρόνου καὶ προσκυνήσουσιν τῷ ζῶντι εἰς τοὺς αἰῶνας τῶν αἰώνων καὶ βαλοῦσιν τοὺς στεφάνους αὐτῶν ἐνώπιον τοῦ θρόνου λέγοντες· (NA28)

"the twenty-four elders throw themselves to the ground before the one who sits on the throne and worship the one who lives forever and ever, and they offer their crowns before his throne, saying:" (NET Bible)

"The four and twenty elders fall down before him that sat on the throne, and worship him that liveth for ever and ever, and cast their crowns before the throne, saying," (KJV)

"the 24 elders fall down before the One seated on the throne and worship the One who lives forever and ever, and they cast their crowns before the throne, saying:" (NWT 2013)

So a question I have is how should βαλοῦσιν be understood--the verb is future active indicative 3rd-person plural of βάλλω (I throw, put, cast, hurl).

See Revelation 12:9.

See http://www.laparola.net/greco/parola.php?p=%CE%B2%E1%BD%B1%CE%BB%CE%BB%CF%89