According to Rob Weir's blog, Microsoft's 325-page OOXML specification for spreadsheet formulas is deeply flawed. From basic trigonometric functions that forget to specify units, to statistical functions, to critical financial functions — the specification does not contain correct formulas that could possibly be implemented in an interoperable way. Quoting Mr. Weir: 'It has incorrect formulas that, if implemented according to the standard, may cause loss of life, property, and capital... Shame on all those who praised and continue to praise the OOXML formula specification without actually reading it.
http://developers.slashdot.org/article.pl?sid=07/07/11/0015240&from=rss