Can't answer your question Rabab, but it brings up another related issue:
the use of one term <FIGURE> in 2 different ways.
In PDFs, all graphical images are tagged with <FIGURE>.
But in HTML 5, it's used for any content, not just graphics, that are
related to the main story content. http://www.w3.org/TR/html5/grouping-content.html#the-figure-element "some
flow content, optionally with a caption, that is self-contained and is
typically referenced as a single unit from the main flow of the document."
The specific reference above for tables reads: "A figure element is used to
give a single legend to the combination of the table and its footnotes."
Never in my editorial mind would I ever call a table a figure, nor the
extracted poem in an HTML5 example on the W3C's website. Jeeze Louise, are
there any professional editors at the W3C who can step in and say "that's
not the best word for that item"?
It would be so helpful to all communities, web developers and document
specialists, if the power players with the W3C could coordinate their use of
the same tag.