i'm trying to book a Qatar Economy ticket in their Economy Saver fare - one step above the Economy Promo.

Their own status credits calculator says that Economy Saver are N, Q and S codes.

Yet, when I try to book an Economy Saver fare, the booking states that it is O class, aka Promo, which gives lower miles and points.

Am I doing something wrong? If so, how do I book N, Q or S?

Thanks.