SEOPressor is pretty useless for an autoblog, but if you're thinking of editing some stuff manually...
SEOpressor only counts the SEO in the content field, not taking into account other areas of your site. It's better to use browser add-ons (like Firebug + SenSEO for Firefox), because they count SEO on the whole page, including navbars etc.
I managed to get 20% keyword density by using SEOpressor and got myself sandboxed lol