Join Date: Aug 2017
Location: Stilllwater OK (SWO)
Programs: AAdvantage ExecPlat, World of Hyatt Globalist, plain "member" of Marriott, IHG, enterprise, etc.
Posts: 1,848
Yes, I have noticed that MCE seat fees are direction dependent, with eastbound being more expensive generally than westbound. (especially true on red-eyes, but my most recent flight still had a mid-morning eastbound MCE upgrade more expensive than the very late evening westbound upgrade).
Honestly, MCE fees are so high nowadays I would be quite surprised if many people are actually paying for them. Indeed, the number of people in MCE serves as a proxy for how many elites are on the flight (since elites can select them for free), thus indicating the likelihood of a long upgrade list or not.