it is between 18-20 years between EPIII and EPIV and the MAw installation is EU and not part of George Lucas Star Wars. And what George says and does with Star Wars is the real thing so he said and filmed the Geonosians to be the brain behind Death Star so then it is like that. Dont mix EU with the canonical stuff
the EU books are a part of the Lucasfilm franchise and it is ther to make money on people who wants to go beyond THE REAL STAR WARS SAGA.
The STAR WARS FILMS does not regard the EU books since that is a separate plot and universe with stories that is not created by George Lucas. It would be the same as if someone wrote a book that is set to be between Two Towers and Return Of a King and it was regarded by some as a true part of the LOTR story
The 'point' of the EU books is, of course, to be read and enjoyed by the people who like them, Mist. They don't HAVE to be part of the same storyline of the films for this to be so. I don't think anyone has any idea if GL reads them or not, but he does use things from them sometimes IF he likes them- whether that is from his own readings or from the suggestions of others made to him, we don't know either. For exampe, rumour has it right now that an EU character will be given a canonical outing in the new film.
But George Lucas never wanted HIS storyline to be limited or changed by what OTHER people had written. This is why EU forms part of an alternate continuity; everyone writing it is aware that what they say has no bearing on what GL chooses to be so in his films and the list of such contradictions is not small.