I know very little about fare classes, but with AC's branded fares the class does not matter. There is a separate thread on this. And I have never seen AC advertise fares by class, only brand. AC can assign any class to a brand as it sees fit (I think). The fare classes you quote are usually comfort or lower if you look at the e upgrade chart. I think you need to book whatever fare brand you want ignoring the fare class it may book into.