[cssom-view] use of "padding edge" in CSSOM view spec makes no sense

CSSOM-view repeatedly talks about the "padding edge" of elements.  The 
definition of offsetX is a good example.

However at 
http://dvcs.w3.org/hg/cssom-view/raw-file/tip/Overview.html/#padding-edge it 
says:

   Content edge, padding edge, border edge, and canvas are defined
   by CSS.

Problem is, CSS defines the padding edge of a _box_, not of an element. 
  And a single element can correspond to multiple boxes, so the 
CSSOM-view definition is somewhat useless.

As a specific example, consider the following testcase (in logical order):

   <span>ABC 1234 DEF</span>

This will render, I believe, as:

   FED 1234 CBA

What is the padding edge here, exactly?  What about if there are some 
line breaks in the text?

-Boris