The red-e-deals are booked in O or N class
The Super-savers are booked in S,V,L,R or M class
The Flexi Savers are booked in either K or B class
The Fully Flexible fares are booked in H or Y class

To earn Tier Points , you need either the more expensive flexi saver fare (BIPOX) or a fully flexible fare (HOX or Y)

Dave