Well, there's no need to discuss it any further, as far as I am concerned, but there seems to be no "explanation" on the "what's new" page, merely a link I cannot open from within Softimage as my workstation isn't connected to the internet:
For highlights of the enhancements to the Autodesk Softimage SDK, see New Features for Softimage 2011 Subscription Advantage Pack (version 9.5).
But you're right, I stand (partially) corrected.
Case closed as far as I'm concerned...
edit: this "what's new" confusion stems from the fact that there's a "what's new" page in the local XSIDOC and a separate one on the Softimage WIKI. Luceric points to the WIKI, while I point to the local XSIDOC.