While this doesn't answer your question, Jorge, here's a little blurb I saw on Slate the other day: ... What are the odds that a movie that is not nominated for Best Director will win Best Picture? Very, very low. Only three films in the Oscar’s past 84 ceremonies have won Best Picture without having been nominated for Best Director as well. The last time this happened was in 1990, when Driving Miss Daisy won the big prize even though Bruce Beresford was not honored at all for his directorial work. For the other two examples, you have to go back a full 70 years: Wings won Best Picture at the first Academy Awards in 1929, though William A. Wellman was passed over in the directing category, and Grand Hotel won in 1932, though director Edmund Goulding was not nominated. Garnering a Best Picture nomination without a directing nod is fairly common—especially so in the last few years, as the former category has expanded to include up to 10 candidates, while the latter has stayed at the standard five. But so far the winners in the former category continue to be the ones that show up in the latter as well. Source - http://www.slate.com/blogs/browbeat/2013/01/10/oscars_2013_b...
But the fact that any discrepancy at all occurs shows a fundamental flaw with the way the awards are structured. And no awards are perfect. The Golden Globes, for example, have a much smaller member size than the academy.