Originally Posted by
WineCountryUA
R space is for GPU, RPU & miles and not CPU. There is no visible inventory for CPU (unlikely NF in PMUA days). Additional the inventory of YBM instant upgrades and buy-ups (PN) is linked, and a used PN space is likely to reduce R space. So there can be lots of upgrade space (R/PN) and none for CPUs.
It is true CPU is done by sweeps but you can not see the inventory (isn't R). UA goal is to fill F as much as possible without CPU such as with late purchasers of YBM fares.
Thanks.
There was NEVER--not once--that I didn't clear into F on an SFO-LAX leg in pre-UA days.
And UA wonders why I have shifted almost all of my international travel to foreign carriers? (Nah, I know UA doesn't care.)