Originally Posted by
xliioper
Not my experience.
Really? What domestic route have you purchased an upgrade that wasn't calculated based on the fare differential? As
findark explained, it's per segment based on the differential at the date of purchase. For a given route, it's therefore fixed, but the actual pricing will depend on inventory. For example, for SFO-PHX, the current lowest differential is $140, which is what the upgrade will price at if there's P available, regardless how much you paid for your ticket.
Originally Posted by
HNLbasedFlyer
Nearly 100% of my HNL-LAX or HNL-SFO or vice versa buyups are $350 regardless of the F price which is always cheaper than buying F outright.
I've seen this on HNL-SFO as well, though IME this is only for the immediate post-purchase upgrade.