Kopity,
Your starting point for ICUS ( by whatever name, it varies by country) is ICAO Annex 1.
Logging ICUS ( by whatever name is used where you are at the time) as ICUS is quite legitimate ---- but it is ICUS, NOT In Command time, a not so subtle difference that eludes many Australian pilots who post on the subject on pprune.
Needless to say, Australia has the most complex,restrictive and impenetrable rules on subject, outside Australia it is a well understood, simple and easily applied concept.
ICUS (by whatever name) counts 100% towards the "Total Aeronautical Experience" totals in your log book
Tootle pip!!
PS: Re. NZ rules, the PIC always remains and logs PIC, a pilot flying ICUS (by whatever name, command practice) always remains under the supervision of the PIC.