[Sabardeyn]

The problem is ZIP files under Windows are both a file type and a folder at the same time. Remember, the ZIP format is one of the ebook file formats that calibre will accept.

So from calibre's perspective, you've directed it to add the ZIP as an ebook file, not to look into it as a folder. As far as I know there is no way to tell calibre otherwise. (And, honestly, it would interfere with adding ZIP format ebooks - and possibly CBZs and EPUBs since they're ZIPs as well with a dummy extension.)

You would have to decompress/unpack the ZIP files. Once done, you could direct calibre to add the resulting folder and all subfolders normally. Calibre will, by default, create a file structure almost exactly like what you're using (it will remove the "Author Name x.zip" level, moving up the "Author Name" folder accordingly).

Of course, the standard warning applies once you're done: you shouldn't be manipulating the files in calibre's library structure manually or through other software - it will eventually lead to errors and possible data loss.