There's still some question about why 18 seconds was placed on the game clock in the closing seconds of the game. (I've had ten phone calls since the game ended about that question specifically) Here's the setup. With :50 left in the game, Carson Palmer took a shotgun snap and hit Andre Caldwell, who ran to the goal line and broke out. Officials downed the play at the half-yard line. The Bengals called a time out with 41 seconds left in the game. Within a few moments, the replay official decided to take a look at the play; the play was eventually upheld. First and goal at the Denver one-yard line.
Cedric Benson powered his way into the endzone for the Bengals first points in the game, which took three seconds, leaving the game clock at 38 seconds. Before the point after attempt, head official Jerome Boger announced to the clock operator that the game clock needed to be reset to twenty seconds. This is where the officials screwed up.
Technically, after a replay review is upheld, whatever existing clock rules apply. If the clock were to keep running without the stoppage because of the challenge/review, then the clock resumes when the play-clock resumes. If Marvin Lewis hadn't called a timeout, then yes, there would be only 20 seconds left on the game clock. However, the officials omitted Lewis' timeout, perhaps believing that Lewis' timeout was in fact a challenge, giving him the timeout back, and resumed the game clock when initiating the play-clock.
After the successful (and unnecessarily breathless) point after touchdown, officials huddled and reapplied Lewis' timeout and reset the game clock with 38 seconds left in the game. Again, no timeout by Lewis and the game clock is at 20 seconds. Timeout by Lewis, and the game clock is at 38 seconds. Got it? The latter former didn't happen so the latter applies.
What was more confusing at the time is that Boger said Cincinnati is charged with a timeout. However, he failed to make the distinction that Lewis' called timeout was before the replay. We can only assume that the officials thought Lewis called the challenge and applied the same rules outside of the two minute warning, when in fact Lewis' timeout only enabled the replay official upstairs additional time to review the play. Other than that, the timeout had nothing to do with the replay.
Now, based on Rule 4, Section 1, Article 3 of the Official NFL Rule Book, which says "game officials can correct the game clock only before the next play is run, including an untimed down or try", the officials shouldn't have been able to change the game clock once the following play was completed. Not only did they change the game clock after Benson's touchdown and before the PAT, they changed it again before the kickoff.
In the end, the officials got the game clock right and no matter what the time was, it wouldn't have changed the outcome of the game if the same sequence of plays take place -- instead of 28 seconds left, there would have been 10 seconds left on the game clock when the snap took place on that play. On the other hand, if Denver only had 10 seconds left, there would be no reason why the Bengals secondary couldn't play much deeper because the likelihood of a field goal attempt would be substantially reduced. Then again, it's not like Denver's offensive play "Have Hall tip pass into Brandon Stokley's hands" didn't work out anyway.
In truth, none of that matters. What happened, happened. I only hope we cleared up the confusion about the mysterious 18 seconds put back on the game clock.