textPath nested inside tspan with dx and dy

I would like to ask for some clarification on how the following snippet of 
svg script should be handled:

<text>
    <tspan x="20" y="20" dx="30" dy="40">
      <textPath xlink:href="#someTextPath">
        Hello World
      </textPath>
    </tspan>
</text>

In this code, should the dx and dy be applied to the current-text-position 
before or after the textPath element sets the current-text-position equal 
to the starting point of the path?  In other words, will ?Hello World? be 
advanced along the path by 30?

Thanks!

-Alex Menzies