Right now the "Custom author info" field is confusing because it is really a custom text field and not limited to 'author' content.
Also, it sometimes displays in "Display settings" and sometimes displays under the subtitle field.
I recommend placing it underneath the subtitle field consistently and shrinking the fields. They would display only if needed by the post type, or if filled in already, similar to subtitle.
This could lead to users writing dates into these fields instead of using the post date field. (Or being aware that the field should be displayed.) I have a proposed solution to that as well, but I'll put it in a different request.
For reference, here is the current KB article on the topic. It could be greatly simplified, along with the instructions in the configure post type screen.
Custom author info
It is possible to add additional meta text fields to a post. This is common if you want to use an alternative date, or use text to indicate some kind of custom content or source, e.g. "LA Times." Here, we added "Fall 2013" to the post, as indicated in the screencapture below. (Note that you would probably not want to add a custom date to a post type which already had a date.) This field is sometimes found underneath the subtitle field, depending on how the post type is configured.
If a meta field matches the title of another post, it should suggest that you put it into the related people/profile fields.
More ideas: in addition to detecting related profiles, detecting dates in the custom meta/text field.