IANAFL, but I would bet money that no agency has ever been found guilty in Federal Court of failing to comply with the FOIA. They always stand up before the judge, hold hands, and chant, "We're understaffed...We're overworked...We have no money...We have no time", at which point the good judge orders them to do better next time and sends everyone on their way.
I'm sure you will remember the success Larry Klayman has had in this sort of thing...