I said it about residents of Greece, not about natives. All residents of Greece, natives of Greece or not, are usually interviewed in Greece.
A person is usually interviewed in the country of residence (in the consulate that has jurisdiction over your residence, to be exact). There are few exceptions, but you do not have a broad choice of place of interview.
Usually only one consulate has that jurisdiction (in case of Iran there are 5).
That is permanent residence. If you are physically present in another consular district at the moment of sending forms to KCC and are going to be present there continuously until the date of interview, that consulate would accept you as well.
I noticed that Riga (Latvia) consulate is not in your 2013 CEAC spreadsheet as well Lithuania, Estonia, Belorussia.
I think that reasidents of these countries are assigned to Warsaw consulate.