Q: When would we stop saying the Mass is ended go in Peace, Alleluia (3x)? I see other Deacons stop at first two weeks.
A: You add 2 alleluias to the dismissal on the Easter Vigil, Easter Sunday, and every day during the octave of Easter, as well as on the Second Sunday of Easter.
Then the double alleluia is omitted until Pentecost. You use it again for the Pentecost Vigil and Pentecost Sunday for the last time.