Plato, Aristotle, and Epicurus all stressed the value of friendship for us “ensouled creatures”, e.g. Nicomachean Ethics 1155a.5 “Friendship is essential for our life;” however, none of their affirmations in the original Greek match the letters of the fraternity’s name (except, of course, for Φ, the first letter of the word for “friendship” [φιλία]). While the founders of Omega Psi Phi may well have been influenced by the view of those philosophers, the actual words those founders came up with in Greek did not quote an ancient author, but were their own, or were at least composed by someone who knew ancient Greek. So Ὠφέλημα Ψυχῇ Φιλία is most likely the fraternity’s original name.
Jerry, your translation is correct, but you’ve transposed the words so that they don’t match the letters of the fraternity’s name. Probably best to uphold the traditional Ὠφέλημα Ψυχῇ Φιλία.