Paid upgrade segment fare coding
If one purchases a pre-departure upgrade on a segment of a UA ticket, how is the fare class of that segment coded? E.g., if I upgrade my A-B segment from T (coach) to R (premium plus), does that segment now, for all means and purposes, have the R fare class?
The reason I’m asking this is to understand whether one could, after this paid upgrade, apply for a PlusPoint upgrade from R to PZ, i.e., business class cabin.