[Plugin: W3 Total Cache] YSlow – "Add Expires Headers" and "Compress components with

Things have been working great! I have reduced the load time for my site by 70% — however — I am stuck on some reports that I am getting from YSlow.

In the “Browser Cache,” I have ensured that I have “Set expires header”, “Set cache control header”, and “Enable HTTP (gzip) compression” all checked. And in each of the three sub-sections, I have the “Cache Control policy” set to “cache with max-age,” and the “Expires header lifetime” set to 604800 for Media, CSS and JS files.

But I am still seeing reports indicating that things are being delivered without expirations — and that the system is not delivering gzipped versions (and yes, they do exist).

Any thoughts on what I should check next?