Originally Posted by nologic
I thought I read the KUP has replaced YUP, or that they both book into P, but I guess I am wrong.
You are.
KUP replaced YUPP, both booking into P. YUP is stil YUP and books into A.
Yes, it's alphabet soup, it's confusing and it can lead to all sorts of problems with confusion over the fare rules. On the other hand, CO offers Z and R discounted First Class fares, which book, conveniently, into Z and R inventory, and are "real" first class fares. None of this -UP bullshlt, which doesn't fool anyone.
Anyway, $1,000 one-way for STL-SFO should get you into first without needing stickers.
That's not what happened.