I forgot to mention I'm going by the Size of the files in the package when uncompressed (ie. installed), using rpm -qi. So the ~120MB openoffice.org-i18n package exapnds out to other 600MB when you install it for example.
Ah, that does indeed seem to use up 925M. looking around on my disk it seems most of this is in: /usr/lib/ooo-1.1/program/resource [599M]
Probably data for different language versions?
Cheers, MaZe.