AFAIK the rendering algorithms of generic outlines versus font outlines are different, in terms of deciding where to rasterize a dot or not (with the former rasterizing more dots on the edge). I suspect the only real fix is customizing the font, and this would be resolution-dependent... :-/
If you do need such customization done there are quite a few people here who could do it for you, including yours truly: hpapazian at gmail dot com
hhp