Now as for the practice in the Antiochian Archdiocese, the Bishop has the perogotive to read the opening psalm, Chant the "Lord I have cried," chant the prokemenion, recite the evening prayer, read St. Symeon's prayer, and chant the dismissal hymns. The only ones of these things that are also not at the perogotive of the priest to do is the opening psalm because he is doing his prayers at this point.
This is pretty standard for the Greeks, except that the priest doesn't attempt to "take" what is the Bishop's "perogative" as far as chanted hymns go.
Personally, I don't like how the Bishops and Priests decide to chant things that should really be done by Cantors, and read things that should be read by Readers. This idea that successively "higher" orders of clergy also contain all the charism and responsibilities of the "lower" ones is, in my mind, too much of a change from the traditional structure of the Church. Some of this is a "clericalism" movement within Orthodoxy; some of it is indicative of the fact that people don't take on these traditional roles of the Church (sexton, Reader, Cantor, Subdeacon) anymore, leaving the clergyman to do more than what he is originally supposed to do; some of it is due to the phenomenon of "horostasia," when the Bishop doesn't vest for a service he is attending. This last point is particularly troubling for me - he is the Head of the Eucharistic assembly, the place and type of Christ, and he doesn't act as Chief celebrant at many of the services.