I believe that you are correct and that the "humpback" version is the modern predecessor of the more elegant old style.
There was some discussion on these in the old forum:
http://www.vikingsword.com/ubb/Forum1/HTML/000136.html
http://www.vikingsword.com/ubb/Forum1/HTML/001032.html
http://www.vikingsword.com/ubb/Forum1/HTML/000758.html
As far as the why's?.....