As was noted prior, if one looks at UA's information

https://www.united.com/page/article/0,,68,00.html

it would appear that the Q-UP fare should book into "B" at best, on a single cabin a/c, as it is the highest restricted coach booking code, since, on two-cabin a/c, it books into A, which is restricted first class. Where some have been successful in getting the booking code changed, B has been the code most utilized, from what I've read.

The COC has some information on fare construction, where multiple and single cabin a/c are utilized, but my knowledge of such is too limited to make sense of that gibberish

http://72.14.203.104/search?q=cache:...&ct=clnk&cd=14

Not a current Q-UP purchaser, but following with interest....

Pat