This would be a good counter to Melvin's argument, suggesting that it would actually be feasible to reduce client loads. It tells us that reducing client loads, even if it might involve a temporary loss of some clients, would solve the problem Melvin uses as his premise -- the difficulty of hiring qualified agents. Having more qualified agents, in turn, would allow the agency to take on more clients in the long run.

What the clients think is not relevant to Melvin's claim that reducing client load isn't feasible because of the difficulty of hiring agents.

Irrelevant. Melvin doesn't deny that smaller client loads might make customers happier, he just thinks reducing client loads isn't currently feasible.

This doesn’t weaken Melvin’s stance that client loads shouldn’t be reduced. If anything, it provides another method of achieving similar results.

This is just more evidence for Melvin's argument. We're trying to weaken his stance.