Originally Posted by drseagrass

I have been regularly seeing this on my spouse's Delta account for Alaska flights where I used a AS Gold MVP guest upgrade certificate or similar mechanism, such as using a companion certificate with a Gold MVP upgrade that also upgrades her to first. This changes the apparent fare basis to U, which isn't on the list of Delta's fare codes that they give credit for. So even though it is a paid ticket eligible for credit, no credit in U. Delta has credited some recent flights when I have pointed this out in emails, but it is getting tedious to continually request credit.