I do not fully understand the ODF vs OOXML standard debate, but the table in this blog on how OOXML writes one simple line of text with the word 'red' in a red font is very illustrative.

The 'ms standard way' to do 'red'.

Word: <w:color w:val="FF0000"/>

Excel: <color rgb="FFFF0000"/>

Powerpoint: <a:srgbClr val="FF0000"/>

The 'ODF way.

ODF text: <style:text-properties fo:color="#FF0000"/>

ODF sheet: <style:text-properties fo:color="#FF0000"/>

ODF presentaion: <style:text-properties fo:color="#FF0000"/>

http://www.robweir.com/blog/2008/03/disharmony-of-ooxml.html