Save as = duplicate
Save = save a version.
Both are in the file menu of text edit and other select applications.
Pretty simple. Same thing just a different name.
Save as really is saving a duplicate file.
Save a version, well you can just use it as save and forget the whole version thing exists if you want to. But it's there if you ever need it.
This works in text edit. i do it all the time.
Upvoted your comment. I don't know why this gets down voted. Ofcourse it's hard and annoying to get used to doing things differently. This change was necessary because of autosave (re-save first(now called duplicate), THEN work).