By the way I have seen that happen over and over again.From 30+ years of experience if you put two mechanics on the same job one of two things will happen.
One of them will go into helper mode and lose all brain function. Now you have an over paid helper
I will take the two top guys in most circumstances. When you put in the lesser experienced guy, production will only go as fast as he can process the job. If he gets overwhelmed, the top guy will have to slow down. Ideally to me, I prefer guys who have worked together frequently. They can often anticipate whet the other needs quickly. I have experimented with different combinations of my guys for years. Generally, an even number of workers is more productive. Most times they pair off. If we have a 5 man crew, I seem to either get lazier, or overwhelmed trying to work alone.