What is the difference between "Top News to Posts" and "Custom News to Posts"?

Hello, I just purchased your plugin. It seems to work just fine so far. However, what is the difference between "Top News to Posts" and "Custom News to Posts" categories on the left side menu? I was posting from the "Top News to Posts" first. When I looked at the other one they look identical. I don't see a difference between them as even the sources in the dropdown menus appear to be the same. I couldn't find any real explanation for why I would use one over the other and for what purpose. Can you point me in the right direction to answer this question? Thank you.