No, because the contents of the first directory itself are only 1MB. If you want something that will sum all the sizes in the directory tree under a directory you want
ls doesn't recurse into subdirectories as a normal matter of course. It just reports on the things that are directly in the location you are looking at. So in your first directory if you add up all the sizes of just the things directly in that directory it can be less than the sizes of the things in a subdirectory. But
ls didn't look in that subdirectory, so doesn't know anything about them when it generates its listing for you.