Sitemap is making mistakes.
It shows one file that actually resides deep in the site as being in the root folder! In the census records, it shows two subfolders in the Ohio folder as being in the preceding New York folder. There are several other places where subfolders and files are listed under the wrong folder.
There are files missing. It's hard to tell exactly which ones without sitting down and comparing the sitemap to the actual file listings (or running a software comparison), but I notice that a story in 24 parts (24 files) has only the first three parts listed. And it's not lising files alpha-numerically, either by filename or title because, either way if it were, the three files would be together, in order. Sitemap indicates there are 18 files in the folder, but there are actually 39 files (plus an index file and a .jpg). The total files indexed by Sitemap dropped by nearly 200 on this run, and I've not deleted any files.
If I can't depend on Sitemap to generate an accurate sitemap, I'm certainly not going to use it. My site is well covered with a Table of Contents and indices to every file, so visitors can find my content much easier with these than with Sitemap. My only reason for adding Sitemap is that it's supposed to assist Google and other search engines, but I certainly don't want the goooglebot using this sitemap!