The premise of the episode is flawed, simply because it is NOT the tradition in the English army for officers and enlisted personnel to swap positions on Boxing Day.
When assigning new roles to each team member, Klinger refers to Kellye as Nurse Nakahara, the actress' real life last name, rather than her character name: Nurse Yamato.
The premise is to swap the roles of officers and enlisted personnel. Lt. Kellye is an officer, so it doesn't follow that she'd be given an officer's duty.
Klinger tells Potter, "you got the carbons in backwards... but that's ok; I could read them in the mirror." Having carbons in backwards would not print the carbon copy in reverse on the second page; it might print the item in reverse on the back of the original, though.