Best source is L.A.S.O.R.S.
You may not both log hours as pilot in command of an aircraft.
The rules in J.A.R. are not the same as F.A.A. land.
In the F.A.A. system you are both allowed to claim Pilot in command if one of you is under the hood and the other acting as safety pilot.
Take it a step further an F.A.A. Instrument Instructor can let you log DUAL as well as Pilot in Command. The reason this was done is apparently to allow you to have enough hours for your commercial rating.
When it comes to applying or doing a J.A.R. commercial, one has to remember those hours don't count as Pilot in command.
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