Valid colwidth values

Hello, We've been going round about on the question of valid @colwidth values.
The documentation on Oxygen's site indicates that you can use proportional sizing using * and numeric values or fixed values using pt, cm, mm, pi, or in.
I don't seen anyone using % values, but given that the allowed values are all CDATA, it doesn't seem this should or would be precluded.
Yet one of our engineers insists that % isn't valid.
Oxygen validates with no errors.
The DITA-OT PDF output seems to render it correctly.
SDL's Publication Manager and Web Client previews seem to render them correctly.
So is there a reason not to use %?
If it is invalid, where is this documented?
Thanks, Bill Burns Content Architect Healthwise < mailto:
> www.healthwise.org< http://www.healthwise.org/
> 208.331.6917 (office) 208.345.1897 (fax) [cid:[email protected]] <<attachment: winmail.dat>>