In one case I'm saying, “These are excellent choices of agents for you to approach with your work and here's how I think you should do it.”
In the second, I am—as my salesman dad would have said—fronting you in. I am personally recommending your work to the agent and my name and reputation are going on the line with yours. Before that can happen I need to read your ms and discuss it with you in great detail. And you probably need to do some more work. Then, if and when it's ready, I will take it to some likely agents.
There's no silver bullet in this business and I have none to offer. But if you're ready to take a crack at prime time, maybe we should talk.