Originally Posted by
findark
xliioper provided the practical answer, but if you're curious:
QHW72NCZ requires Q space and is based on the Q- fare family (Q), is a high-season fare (H), for travel on weekends or market-normed "high period" days of the week (W), a 7-day advance purchase (7), minimum stay of 3 days or Saturday night (2), non-refundable (N), books into Comfort Plus in W class (C), and is in fare series Z.
LHW46NCZ is a W fare with L space, high season weekend, with a 14-day AP and 7-day/Saturday night minimum stay, also non-refundable.
Yes, good info. As noted, the 'C' in second to last letter indicates the fare books into W class. If second to last letter is an 'I', the fare books into the C+ S booking class. The S class version of fares is $150 cheaper on a each-way basis than W fares (the Q fares are shown below, but differential is same for the L fares). If there was S bucket open in one direction, total price would be $150 cheaper and price would be $300 cheaper if S bucket was available in both directions.
