Hi:
I understand your point of view. If the code was written a LONG time ago (like in SAS 8, then it would have been OK because SAS 8 and ODS HTML created HTML 3.2 compliant tags by default. Microsoft "likes" 3.2 compliant HTML tags. So that code would have worked in SAS 8.2 with ODS HTML.
Then, in SAS 9, ODS HTML started creating HTML 4.0 tags by default. Many web browsers were not ready for HTML 4.0 (because of inline <STYLE> section) and there was a registry switch you could flip in SAS to automatically create 3.2 tags with the simple ODS HTML syntax.
A lot of folks who used SAS/IntrNet did this because it was easier for them to flip the switch on the Application Server in SAS 9 then to recode all their programs to invoke ODS HTML3. Microsoft parted ways with the W3C folks over HTML 4.0 and that's actually about the time (2000) when Microsoft came up with their own flavor of HTML. So it is possible that your folks "flipped the registry switch" with SAS 9.0 or SAS 9.1 instead of recoding everything to ODS HTML3.
Honestly, I don't think that HTML 4.0 tags with mso-number-format as a style property ever opened in Excel correctly -- but you'll have to check with Tech Support on that. As I said, I no longer have 9.1.3 to test with. The mso-number-format and other mso- style properties were created by Microsoft about the same time they created their own flavor of HTML.
So the first time I ever used mso-number-format, was with ODS HTML3 and ODS MSOFFICE2K -- both are HTML "flavor" of destinations that create the kind of HTML tags and style definitions that Microsoft Office is happy with. For example, if you run the code that I previously posted, using STYLE=SASWEB, you will see that the ODS HTML3 and the ODS MSOFFICE2K output files both use the blue and white style specifications when the files are opened in Excel; however, ODS HTML (the 4.0 tags) style looks icky in Excel, mostly because Excel does not like the HTML 4 in-line style section.
cynthia