hmm.. the wording of the article ,which is linked in the original post, is pretty fuzzy ...
they say "Der japanische Elektronikriese setzte von seiner ... Playstation 3 (PS3) _vor_ Weihnachten rund 136.000 Einheiten ab." , which translates to "the japanese electronic giant sold 136k units of their PS3 _prior_ to christmas" - Do they really mean november+december numbers with that or just november + december 1-24 or sth. like that?
and a second one:
"Laut GfK hat der Konzern von _März bis Dezember_ 2007 insgesamt 309.000 PS3 verkauft." - According to the GfK the company sold 309k PS3s from march to december 2007. - Do they mean march -> end of december or march -> beginnig of december ?
depending on the interpretation of this article PS3 might have been at sth above 445k (309k march-> beginnig of december ; 136k "prior to" christmas in december ) at the end of 2007 in germany or at sth largely above 309k (309k march-> beginning of december ; 136k "prior to christmas" in november+december) or at the 309k the OP posted ...
badly written article in my opinion, although I'm fairly sure ,that the interpretation the OP made, might be the true one