When I got mine i looked at the specs for the oil and thought nah, I'm going a 40 then I found out they had changed it from 30 anyway, doing some research on it I found that the L360 version of the engine in the US was showing some drama in the RAMs, yanks only saw the diesel in 14? and it was around the same time they changed the oil filter, a view which sounded good to me, was the RAMs worked harder and the original oil spec which was more for getting good economy figures wasn't up to hard yakka....
The L360 VM Motori engine in the US seems to have more pollution crap and was in the poo for emission defeat devices, less HP than the A360 version in Export models which has less pollution crap, a great engine until AdBlue and stop/start added but all academic now...........
Many manufacturers have had oil spec changes as its all about the eco stars on the windscreen, price of servicing and the dollars per year spent more than whats really good for the running gear longetivity......... Its the "Look At Me, Look At Me" factor........
Well thats my take on it anyway .......................