I think that is the way it is meant to be. Relative positioning takes the element from where it woud be if the position was static and shifts it by top and left values. It does not affect the position of the neighbour elements.
See the CSS standard for details:
http://www.w3.org/TR/REC-CSS2/visuren.html#comparison
If you explain what kind of layout you are trying to achive I may be able to help you