Geoff and Bravo,
The system is not incapable, it was just never designed or intended to function that way, so far.
There are misgivings about the requirement for a specific background experience, it may help the SFI establish some common ground with the trainees, thus making his/her job easier but deep down inside what counts is systems and procedures knowledge, and that applies to any helicopter type.
One major O&G support operator does not require that their "loaned" SFIs have offshore experience, it requires instead for their instructors to be trained to its standards.
Also, just because you are flying the sectors every day for six weeks and a lifetime, doesn't necessarily mean that it will improve your knowledge of the aircraft, quite the opposite in fact in some environments and types of operations (I speak from personal experience from both sides of the fence if it may help).
It's a Type Rating course, and I cannot quite recall what part of the EASA or FAA or CASA or ANAC or TC RFMs include OSAPs and ARAs or PIC Judgement in dealing with a deceiving customer dispatcher.
All I can find with regard to Offshore operations is in Suppl 9, 12 and 50 of the RFM.