We have had some general reasons for the use of KEP elsewhere on the blog, but one thing we have not done is shown detailed evidence for pronunciation here. The following passage of poetry is from Callimachus (c. 310-240BC), from the early Koine period, which began with the conquests of Alexander the Great (died 323BC). Poetry is good for reconstructing sounds because of the use of rhyme and other aural devices. This particular poem is variously numbered as Epigr. 28, 29, or 30 (e.g., LSJ calls it both 28 and 30):
Ἐχθαίρω τὸ ποίημα τὸ κυκλικόν, οὐδὲ κελεύθωι
χαίρω τίς πολλοὺς ὧδε καὶ ὧδε φέρει,
μισέω καὶ περίφοιτον ἐρώμενον, οὐδʼ ἀπὸ κρήνης
πίνω· σικχαίνω πάντα τὰ δημόσια.
 Λυσανίη σὺ δὲ ναιχὶ καλὸς καλός — ἀλλὰ πρὶν εἰπεῖν
τοῦτο σαφῶς, Ἠχώ φησί τις ‘ἄλλος ἔχειʼ.
I despise the circular [that is, conventional] poem, nor the road
do I enjoy which carries many here and there,
I hate also the wandering one that is loved, nor from a spring
do I drink; I loathe everything publicly held.
But, Lysanius, you are indeed beautiful, beautiful — but before
Echo says this clearly, someone says “another has [Lysanius]” (my translation).
The bold words are set up in an echo. Echo was an Oread who was tasked by Zeus with stopping Hera (Zeus’s goddess wife) from discovering Zeus’s affairs with the nymphs by having longwinded conversations with Hera to give Zeus time to escape detection. When Hera found out, she punished Echo by making her only able to repeat the last things that someone spoke to her. Later, she fell in love with Narcissus and died of a broken heart after he rejected her and fell in love with himself, leaving only her voice to echo.
Like Echo, Callimachus is spurned by his love interest. In this poem, the poet is hoping that Lysanius will echo back the ναιχὶ καλὸς καλός, but instead someone else informs the poet that Lysanius “wanders” in his love by saying ἄλλος ἔχει. This makes a kind of decaying echo in KEP, while it is obscured in the traditional Erasmian pronunciation (the following is in approximate English pronunciation rather than IPA):
While καλὸς and ἄλλος sound the same in Erasmian with inverted accent placement (last syllable-first syllable), ναιχὶ and ἔχει do not. KEP, however, treats the αι monophthong as equivalent to the ε AND treats ει as equivalent to ι. Thus, aurally, KEP keeps the same inverted pattern with similar sounds, like one would find in a decaying echo. While this example does not prove all of KEP (such work would take many more samples of this and other differences), it demonstrates the KEP is clearly closer to Callimachus’s pronunciation than Erasmian, which obscures the aesthetics of the poem.