From BDAG:
συντέλεια, ας, ἡ (orig. ‘community contribution’ [the basic semantic component relates to someth. that complements someth. already present]; in various senses Pla., Demosth. et al.; ins, pap, LXX; En 106:18; TestSol; TestJob 4:6; Test12Patr; ApcEsdr 2:31 p. 26, 25 Tdf.; Aristobul., in Eus., PE 8, 10, 9[=Denis p. 219 ln. 11f; Holladay Fgm. 2, 55 p. 138]; Jos., Ant. 15, 389; 20, 262; Tat.; Ath., R. 12 p. 61, 31 ‘increment’; Theoph. Ant. 2, 31 [p. 176, 14] ‘posterity’) in our lit. only in a temporal sense: a point of time marking completion of a duration, completion, close, end (Polyb. 1, 3, 3; 1, 4, 3 al.; SIG 695, 13 [II b.c.]; POxy 1270, 42 [II a.d.] σ. τοῦ ἔτους; LXX; Iren. 1, 6, 1 [Harv. I 53, 2]) συντέλεια (τοῦ) αἰῶνος the end of the (present; αἰών 2a) age (TestBenj 11:3; TestJob 4:6) Mt 13:39f, 49; 24:3; 28:20. τοῦ αἰῶνος τούτου of this age 13:40 v.l., 49 v.l. τῶν αἰώνων of the ages (TestLevi 10:2; Did., Gen. 115, 19. Cp. in gnostic speculation σ. καὶ ἐκπύρωσις τοῦ παντός Hippol., Ref. 9, 30, 8) Hb 9:26. τῶν καιρῶν (Da 9:27) Hv 3, 8, 9. τοῦ κόσμου Mt 13:49 D. ἐπʼ ἐσχάτων τῶν ἡμερῶν τῆς συντελείας in the last days of the consummation (of the age) Hs 9, 12, 3 (cp. TestZeb 9:9 καιρὸς συντελείας; ApcEsdr 2:31 τὴν ἡμέραν τῆς συντελείας; cp. ViJer 13).—DELG s.v. τέλος. M-M. TW.
From TDNT as it pertains to its usage in Daniel:
3. As an apocalyptic tt. συντέλεια is common in Da. LXX for קֵץ to denote the “end,” so καιρὸς συντελείας for עֵח קֵץ at 11:35; 12:4 (also Θ), and with no corresponding HT 12:7; ὥρα συντελείας 11:40 (but ὥρα καιροῦ 8:17), while Θ prefers καιροῦ πέρας 8:17; 11:35, 40; 12:9. Da. LXX also uses συντέλεια for קֵץ the eschatological “end” at 8:19, cf. too 11:27; 12:6 (in all these Θ πέρας) and 12:13a (Θ the same); συντέλεια ἡμερῶν is the transl. of קֵץ הַיָמִין at 12:13b (also Θ). συντέλεια for “end” in a more gen. sense occurs for קֵץ at 9:26 (twice); 11:6, 13, 45;6 συντέλεια καιρῶν with no HT 9:27. The noun is always an apocal. tt. in Test. XII Zeb. 9:9 ref. to rejection ἕως καιροῦ συντελείας → line 35 f.); B. 11:3: ἕως συντελείας τοῦ αἰῶνος. Levi is not guilty of the transgression of the temple cultus by his sons ἐπὶ τῆ συντελείᾳ τῶν αἰώνων, i.e., at the time of the author, L. 10:2, cf. R. 6:8. συντέλεια corresponds to קֵץ, but sometimes in the transl. the idea of completion in the sense of eschatological fulfilment may be stronger; in Judaism the “end” is the conclusion and related events.
"Eschatological end" fits the usage in Matthew as well - but again, even a simple "end" is understood for its usage in Daniel 9:26.
Furthermore, as neither I nor Jonathan appealed to any English translation, bringing them up is a bit of a red-herring. However as you have done so, I would also like to point out it isn't just some English translations which translate συντελείας and τέλος by the same word:
Matt 24:3:
Y sentándose él en el monte de las Olivas, se llegaron á él los discípulos aparte, diciendo: Dinos, ¿cuándo serán estas cosas, y qué señal habrá de tu venida, y del
fin del mundo? (Spanish Bible Reina–Valera)
Sedente autem eo super montem Oliveti, accesserunt ad eum discipuli secreto, dicentes: Dic nobis, quando hæc erunt? et quod signum adventus tui, et
consummationis sæculi? (Clementine Vulgate)
Matt 24:14:
Y será predicado este evangelio del reino en todo el mundo, por testimonio á todos los Gentiles; y entonces vendrá el
fin. (Spanish Bible Reina–Valera)
Et prædicabitur hoc Evangelium regni in universo orbe, in testimonium omnibus gentibus: et tunc veniet
consummatio. (Clementine Vulgate)
Two non-English translations which translate the two words using the same word in the target language. This is why it's best not to bring up translations
This reeks very much like the
ἀγαπάω /
φιλέω debate of John 21. There really is no hidden meaning between the usage of two different words to mean the same thing.