When doing SDC is it normal for the new flights to be booked in full Y class instead of the original paid fare class. About 3 weeks ago I did a SDC on a SAT-JFK ticket that was originally booked in L and the new flights were booked in Y and I earned 50% class of service bonus for both segments. Today I did another SDC on a U ticket and again both of the new flights were booked into Y. The miles have not posted yet but I imagine that they will earn the class of service bonus since it shows Y instead of U. Does this usually happen or was I just lucky?