I would assume that it'd be harder to challenge ballots once they've been certified. That's one of the reasons that they didn't want the Florida results certified in 2000 -- it would've meant suing to overturn the election results. (It still was but they weren't "results" yet ... yada yada yada ... forget I brought that up ... not responding to it...)
Catherine Harris certified Bush as the winner but the rats found judges who demanded additional recounts. Cerification does not seem to stop the rats.