Originally Posted by
ljwobker
Is there a well defined mapping of what coach class fare buckets are mapped to which first class fare buckets when doing (domestic) -UP fares? (Assuming they're still even called that...)
It's defined by the fare. For example,VAP00UPN is a V that books into P. HAD00UPN is an H that books into D. If you have an EF subscription, you can see all the fares for a particular route.