Seems like they would have to be different people, can't imagine (barring Shena or IT glitches) how that would happen otherwise.

Certainly there could be some people already in C+ who appear on the F list and don't appear on the C+ list, but that's the opposite of what you observed.

Though in theory the person ahead of you on the C+ list should have also appeared on the F list? Hard to imagine why someone would request a C+ upgrade but not an F upgrade, unless they just ticked the wrong boxes on DL.com.