Hummingbird Minification filenames logic

Good Evening,

Let's say I have a site using Hummingbird and its minification feature that combines some CSS files in the header. Now I update the theme (or plugin), the site still shows the old CSS. It looks like the new CSS got minified and combined, because when I reload the minified css file (cmd + r) and then reload the site, the new CSS is being displayed properly.

Is it possible that the minified CSS file uses the same name for the new file and therefor does not tell the browser to download the new styles? Is there a solution that I don't have to worry about that?

Thanks a lot
Stefan

And does anyone know if a theme or plugin update triggers WP Super Cache or W3 Total Cache to empty the cache?
(I know these are not wpmudev plugins, but since wpmudev does not have it's own caching plugin (yet) maybe another member knows the answer to this question.)