I talked to my priest about this..and he speculated that perhaps the Orthodox were granted a waiver regarding the common prayer part of their praxis...
Even tough your priest speculated wrongly, I wonder if that really would have made a difference.

David Wagschal (OCA), John W. Morris, Vicken Aykazian, H.G. Serapion, and "Bishop" Demitrios Couchell (GOA) lead participants in evening worship. They all prayed as one. Attendees included...
Bishop Vicken Aykazian  	Diocese of the Armenian Church
Commissioner W. Todd Bassett 	The Salvation Army
Bishop Stephen Blaire 	US Conference of Catholic Bishops
Most Rev. Tod D. Brown 	Catholic Diocese of Orange of California
The Rev. Rothangliani Chhangte 	American Baptist Churches, USA
Rev. Dr. Seung Koo Choi 	Korean Presbyterian Church in America
Mr. Bonn Clayton 	Nat'l Assoc. of Congregational Christ. Churches
Bishop Dimitrios Couchell 	Greek Orthodox Archdiocese of America
Sister Joan Delaney 	Roman Catholic Church
Rev. Dr. David Engelhard 	Christian Reformed Church in North America
Bishop C. Christopher Epting 	Episcopal Church USA
President Jeff Farmer 	Open Bible Churches
The Rev. Wesley Granberg- Michaelson 	Reformed Church in America
The Rev. Dr. Roberta Hestenes 	World Vision
Bishop Francis J. Kane 	Roman Catholic
The Rev. Arthur Kennedy 	United States Conference Of Catholic Bishops
Bishop James D. Leggett 	Int'l Pentecostal Holiness Church
The Rev. Michael E. Livingston 	Int'l Council of Community Churches
The Rev. Rafael Luevano 	Ecumenical & Interreligious Affairs Officer
The Rev. Carlos Malave 	Presbyterian Church USA
Dr. Kevin W. Mannoia 	Free Methodist Church
The Rev. Thomas R. McGowan 	Roman Catholic
Sister Joan McGuire 	Roman Catholic
President Grant McMurray 	Community of Christ (Observer)
The Rev. A. Roy Medley 	American Baptist Churches USA
Ms. Gail Mengel 	Community of Christ (Observer)
Father John W. Morris 	Antiochian Orthodox Christian Archdiocese of NA
Mr. Stanley J. Noffsinger 	Church of the Brethren
President Glenn R. Palmberg 	Evangelical Covenant Church
Friend Ben Richmond 	Friends United Meeting
Dr. Ann K. Riggs 	NCC Faith & Order Commission (Observer)
The Rev. Dr. Bruce Robbins 	United Methodist Church
The Rev. Ronald G. Robertson 	US Conference of Catholic Bishops
The Rev. Dr. William G. Rusch 	Foundation for a Conference on Faith & Order in NA (Observer)
The Rev. Gabriel A. Salguero 	Missionary Pentecostal Churches of God (Observer)
Bishop Nicholas J. Samra 	Melkite Catholic
Dr. Robert E. Sawyer 	Moravian Church
The Rev. Jim Schrag 	Mennonite Church USA
H. G. Bishop Serpion 	Coptic Orthodox Church
The Rev. Ronald J. Sider 	Evangelicals for Social Action
Dr. Gilbert W. Stafford 	Church of God (Anderson, IN)
The Rev. Lydia Veliko 	United Church of Christ
Dr. Daniel Vestal 	Cooperative Baptist Fellowship
The Rev. Bert Waggoner 	Association of Vineyard Churches
Mr. David Wagschal 	Orthodox Church in America
The Rev. James Wallis 	Call to Renewal/Sojourners
Dr. Robert Welsh 	Christian Church Disciples of Christ
The Rev. Don DiXon Williams 	Bread for the World
I didn't see the "Agape Church", which I've seen in Tennessee; I guess that's a good thing.