Just to clarify what Onehunga has said:
Aviator rent their twins out to two instrument-rated pilots at once. One is at the controls, under foggles, and logs P1. The other "logs" the time as safety pilot.
Under FARs, there is no problem with this - it's legal, and a very common practice. Under JARs, though, it's not allowed. Any time which you are not at the controls can not be counted towards any JAR license requirements.
Nothing wrong with them, though, as far as I know - it's just that you have to double their quoted price to get something that's comparable with anywhere else you're looking at.
FFF
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