> sorry i should clarify that identical files were 
> actually being re-downloaded even though nothing has 
> been updated.

Even image files were downloaded twice, or just html 
pages? Many servers are generating on-the-fly dynamic 
pages, which can not be cached. 

You can check that by activating 
the 'Options'/'Experts only'/'Debug' chechbox and look 
at the hts-ioinfo.txt generated file: you will see 
many requests with "If-Modified-Since" or "If-None-
Match field, and responses with "200" returncode 
(retransfer) instead of the "304" (not modified) 
returncode.