My understanding was that the word "Choice" indicated that the note was not just UNC, but had desireable qualities such as well centered design, free of counting marks (like little creases in the interior of the note from being counted), the inking is strong throughout the note, no ink smudges from the adjacent note in the strap, etc....
its the same as coins an item might be uncir choice gem or above gem just coz an item is unc it does not necessarily mean it cant be betetr than unc it all depends on the listing
