In St Cyril’s Liturgy it says the following at the Litany of the serving Priest:
“(In Moses tune)
That I may bless You at all times, all the days of my life.”
In other texts, it says “He then cries out in the Ancient Tune”...what then is the “Moses tune”, why is it called that...?
As for why Moses is related to the servant priest, I don’t think I’m smart enough to give my opinion on that :D maybe some smarter people can give a more satisfactory answer to these questions
The thing about St Cyril's liturgy is that we have lost almost all it's hymns, except some, 5 I think, that were recorded by M Tawfik and M Mikhail. People wanting to "restore" tunes of the anaphora probably saw that mention and tried to figure out the tune... Not knowing that there is a tune for it already that is recorded.