Clarification about %%excerpt%% ?

For my posts and pages, I’m pretty diligent about writing both custom meta descriptions and custom excerpts. (Different contexts, different needs, yep?) So in prep for my site launch, I just opened things back up to robots, double-checked my WP SEO settings, and subsequently noticed Google was indeed crawling my site but was using autogenerated meta descriptions.

So in re-double-checking (not quite triple-checking) my WP SEO settings, I noticed I left the post/page meta description template box empty, assuming that meant it would use the custom meta description I wrote with each post.

However, while og:description does appear, meta name="description" does not.

I’ve since gone back and added %%excerpt%% to my meta description template box.

So as I wait for Google to recrawl, I’ll ask my clarification question: is %%excerpt%% only the WordPress excerpt, or does that actually mean the custom WP SEO meta description? And if it’s not the WP SEO meta description, what am I missing?

http://wordpress.org/plugins/wordpress-seo/