I took a look at one of the sub-CGI summary pages:
http://www.ispreview.co.uk/cgi-bin/ubb/ultimatebb.cgi?category=1 This comes out as 15,308K and is clearly not being compressed, so I'm not sure how you saw it being compressed.
I think I have the same issue as Allen because we just moved servers and I asked for those modules to be installed, which would thus be the very latest ones.