The Powerjokes are especially sensitive to foaming as the injectors are actuated by engine oil at extremely high pressure. The Ford literature indicates that foaming can be a problem, especially for the 7.2 DI. Since the change interval was lengthened somewhat for the 6.0, we assume there is less of a problem, perhaps because the early 6.0s apparently added coolant to the engine oil, which one assumes would really actuate an injector at high pressure.
The Cummins B does not. There is no warning concerning foaming of engine oil that I am aware of. Cummins does suggest that synthetic is a waste of money for that engine as it is almost immpossible to wear it out using dino.
The Isuzu would undoubtedly use rice bran oil, so I wouldn't know if foaming would be a problem there.