I gave up on the automatic numbering and found that when I put a number and period in front of a paragraph, Evernote reads it as a numbered list.
So I put a bullet list after a numbered list item.
I spaced down and typed the next number in, and Evernote picked it up as a numbered list item and used the number I had typed.
I still had to indent the bullet lists, which Evernote changed to a lower-level bullets, but I'm not that picky.
I'm using Evernote 6.6.4.5512 on Windows 7.