Our colleagues Ioannis Papathanasiou and Nikolaos Boukas have already written an article about this. A part of it can be found
here (p. 1ff.)
I find the claim "If the hypothesis under study proves valid, the importance of Egypt and of the provincial regions of the Byzantine Empire more generally are reconfirmed with regard to the creation and dissemination of eastern liturgical musical tradition" on p. 1 strange, but without seeing the rest of the article, I cannot give my judgment. The mss in question are of Coptic origin (or so does Crum say) and date from the period when Copts are already separated from the Orthodox Church. No direct and safe inference can be made from these mss, I think. In any case it is not at all clear that the melodic tradition represented here is Greek and not Coptic proper (even if it dates from some older period). The fact that the texts are in Greek does not matter much: Copts still chant some (very few) parts of their services in Greek (see e.g.
here the tracks The Anaphora and Agios agios, agios), but it would be quite a bold statement to make inference on the relationship of the melodies with their supposed old Greek originals.