Interesting theory about the continuity error.
Hey I just had a thought. Ok, say the consistency error was not an error, and Tyler, being the perfectionist that he is, did, in fact, reconnect the wires. Now we have an active bomb in all of the buildings, but the one Jack and Marla are in has a timer delayed by the amount of time between Tyler and Jack's fight and Tyler's reconnecting of the wires.
Now at the end of the movie, the penis shows up right before the fade to black, indicating that Tyler's mark is still present.
Could this be an indication that Jack and Marla's building did, in fact, blow up after the film reel ends? It makes perfect sense, as the building's final detonation would have be a few minutes after the initial detonation of the first five or six buildings. And now that I think about it, in the CGI sequence at the beginning, the timer in the bullet-pierced van was counting down to zero, was it not?
Then again, I might be wrong.