Flights are S0 N0 Q0 O0 G0 (in addition to X0 for BE) for most flights from April through mid-September leaving only pricey V fares available for purchase. The flights with X1 starting in mid-September also tend to be S1 N1 Q0 O1 G1. So if you are buying more than one fare, you are again stuck with pricey V fares. Note that in order to purchase a BE fare, there is a dual-inventory check. There must be both inventory in X and the underlying coach fare basis bucket for the BE fare.