Memories....
Normally no1 (the far left) is loitered because there is no generator on that engine. Loiter will save a lot of gas and give you about 1 more hour onsta. It is because the other engines are now running hotter (more efficiently) to obtain the same loiter IAS. The big problem was a lot of rudder required to balance with high power on the other engines. That's one of the reasons I tried to avoid loitering. You would shut down no 4 to really prolong time onstation, but the risk is you are now down to 2 generators. And you can't do this until you have burned off significant fuel.
During the current SAR, I can't imagine the p3 crews would have loitered in the initial search areas far to the southwest. You need to account for the possibility that the engine won't restart, and that you might be restricted to 10000' due loss of pressurisation (3 engine 10 config). An unlikely scenario, but that was SOP back in the day.