Custom URL like count, how does it work?

In your settings, under the custom URL option, it describes: ” Enter custom url that will always be used for sharing. You can enter your root website here so counters will show statistics for your whole website, not for each page individually.”

So if I put in my home page url here, would each page or post then show the facebook like count that is the aggregate of all the current facebook likes accumulates on all the posts combined? And then if later made this field blank again, would the facebook likes on each post or page then revert back to what they were before changing to this option (the one like count for whole site)?