I fail to see how your solution is
less complicated than adding a field switch. Amongst other things, it doesn't work unless each line is a separate paragraph, which compromises any Style-based document formatting such as space before/after, indents, etc, all of which increase the difficulty of maintaining the document and can lead to document instability.
You might also note that the thread to which you were replying was last updated nearly three months ago. I very much doubt either of the original posters is still looking for a solution. Since your posts here are little more than a repeat of what you've posted elsewhere (e.g.
http://social.technet.microsoft.com/...pty?forum=word), I trust I'm not going to have to point out the deficiencies of your approach all over the web...