I'll take my cue from the U.S. Copyright Office's FAQ, particularly this Q&A:

Q: How much do I have to change in my own work to make a new claim of copyright?

A: You may make a new claim in your work if the changes are substantial and creative, something more than just editorial changes or minor changes. This would qualify as a new derivative work. For instance, simply making spelling corrections throughout a work does not warrant a new registration, but adding an additional chapter would. See Circular 14, Copyright Registration for Derivative Works, for further information.

Source: www.copyright.gov/help/faq/...tml#change

There is no hard and fast definition of "substantial and creative" here, so I don't know if moving paragraphs around qualifies. I'd still say to check with the individual editor. Insofar as a title change goes, titles are not copyrightable. Granted, story submission and copyright are two different things, but at the moment I can't think of a closer analogy.