Originally Posted by
ijgordon
They're certainly more related than not, IME. There's almost zero chance of getting 3 Cs plus 2 Us if the flight shows C3 U2.
+1
Both booking classes represent seats AA is willing to let go without receiving cash payment for a business class fare (or stupid amounts of miles for an AAnytime award). AA may have some preference as to SWUs vs. miles + copay, which may explain variance between inventory in the two buckets... but you can be sure they are not additive.