Originally Posted by
MileageManager
Another thing I notice is there would be a bunch of names on the F list, several more beyond the open slots. But there would only be one name on the C+ list - mine.
Yep, that makes sense and is an expected occurrence.
You may already know this, but in case you don't since you mentioned you're a FB elite and not a DL "native"

. You have the ability to elect to not be automatically added to the C+ upgrade list (or to remove yourself if you're already on there) - this can be done on DL.com or by calling in (and I'd assume with an airport agent).
It seems that many DL regulars voluntarily remove themselves from the C+ upgrade list to avoid being upgraded from an aisle exit row seat to a middle C+ seat, for example.
Also remember that any upgrade-eligible pax already in C+ will appear on the FC list, but not the C+ list, so naturally the C+ list will often be shorter.