I think it is also important to differentiate how commercial labs and amateurs works. On one side big tanks with a minimum of 4 liters and up to 50 liters of developer where a humble piece of film pass though it avoiding aireation as much as possible; on the other side an amateur on the bathroom processing film in a small tank with 0,5 to 1 liter doing manual inversions. I don't think both can apply the same replenishment practices and even in some cases it will be not possible for the amateur.
In a Jobo-like rotary processing aireation meets also a very low volume of working solution. I can process in my Jobo CPP2 a 35 mm roll with just 125 ml, or process a 8x10'' paper sheet with 100 ml. The price to pay is that most working solutions are one-shot, still expensive from a large commercial lab point of view but very covenient for some amateurs like me with ocassional use of the darkroom.
In a Jobo-like rotary processing aireation meets also a very low volume of working solution. I can process in my Jobo CPP2 a 35 mm roll with just 125 ml, or process a 8x10'' paper sheet with 100 ml. The price to pay is that most working solutions are one-shot, still expensive from a large commercial lab point of view but very covenient for some amateurs like me with ocassional use of the darkroom.