The results are cached, so if you only change the cutoff day setting then access the same url, you won't see any change in the results. As a test, you can force it to make a new request by changing certain parameters on your request, for instance like this:
http://www.wyoming-rc.com/forums/ext...ids=9&nohtml=1 and you see the Rss Test thread you started. So I think your problem probably was the cutoff and after the cache expires it will start working.