No, the feed should refresh every time, since the expiration time is set to 0. The script checks the created time of the cache file to find out if it should be updated.

If you want to have this module working with no cache at all, your site will get slow. It will have to fetch the feed every time your page is loaded.

Finally, i really don't get what you are trying to achieve.
In the beginning you wrote:
"Because I'd like the module to be always uncached, so the feeds would always be updated."
And in the end:
"So, the only module that doesn't allow me leaving it cached for long is Feed RSS" .