How to check if supercaching is actually serving static pages?

Hi,

I just installed WP-supercache on a wordpress 2.5.1 blog.
It’s activated and all and it even says 15 cached pages and 7 supercached pages, but when i look at the source code of the page, there is the following line at the bottom:

<!– Dynamic Page Served (once) in 0.217 seconds –>

Shouldn’t there be something like “<!– Cached page served by WP-Cache –>” or <!– Cached page served by WP-SuperCache –> ?

How can I make sure that the page is actually cached? Also, when I open
another browser I get
<!– Dynamic Page Served (once) in 0.241 seconds –>
<!– super cache gz –>
So a different time in seconds… Does this mean the page is not cached at all but dynamically generated each time?