The term PIC is obviously used to mean more than one thing. To a job interviewer, it means time when you were fully in command of all aspects of the flight. However, the logging of PIC time is addressed by the FAA in only one place, part 61. (The definition in Part 1 is included in the part 61 language.) If you are fully rated for PIC in the airplane and are sole manipulator of the controls (from either seat, revenue leg or not) it should be logged as PIC. (The recent change to SIC type ratings leaves some ambiguity about whether an SIC-rated pilot can log PIC time; that language needs to be cleaned up.)
Bottom line: your logbook time should be entered only as defined by Part 61. However, for the job interviewer, be prepared to differentiate those flights where you were not the pilot signed for the aircraft.