Hey Peter (and everyone else),
Finally caught the scene in question. My own reaction is that it's funnier than the other twelve minutes of the clip. Obviously, one's mileage may vary. Here are a few things that were running through my mind whilst everything was going on:
1) I wonder if the repeat is a sly commentary on Cao Cao's recruitment of Zhao Yun/Zilong (see Liu Bei's recruitment of Zhu Geliang/Kong Ming.)
2) I wonder if it's a commentary on Cao Cao's supposed sly intelligence (the term "guicai" comes to mind.) If I could summarise Three Kingdoms in a a few sentences Cao's initial conquests were stacking superior forces against neighbors and then getting them to surrender because of their fear of supposedly insurmountable odds. Flash forward to Red Cliff and afterwards when Cao tries this exact strategy over and over again against Sun Quan and Liu Bei (Liu's earlier losses before this point were before he had established a formidable state/kingdom of his own.) Irrespective of Cao's infamy in ancient Chinese historiography, he was basically a skilled administrator able to supply his armies with weapons and grain. A competent strategist, you'll note the major heroes of the age sided with Liu and Sun instead. Anyway, Cao's general strategy was to build up a large army and send it against a foe, usually causing them to surrender because of the awesome numbers of incoming foes. This doesn't work against Liu and Sun because they are actually pretty good strategists and not bowled over simply because of the large numerical disadvantage.
The story of Three Kingdoms is Cao doing this bit over and over again even though Liu and Sun's distance from Cao's home base prevented Cao's armies from fighting an actual military campaign because supply lines were stretched far too thin to do anything save just show up on Sun and Liu's home turf. Yet Cao Cao keeps doing this over and over and over and over again... it's like the definition of insanity: doing the exact same thing over and over again yet expecting a different result each time.
3) Cao and his nephews were known for being great poets of their age and part of their poesy involved repetition for ironic effect.
4) Based upon the Hard Boiled baby shotgun/Rec Cliff baby rescue spoof, Jeff Lau's obviously not working on this level/considering from this angle. So, just strike what I just said from memory.
5) I think it probably lost likely to be a reference to the the absurdity of repeating events found in the earlier Stephen Chow "Chinese Odyssey" movies. I could invoke Nietzsche and the "eternal return of the same," but that's just me trying to add heft to make my argument sound bigger than it actually is. As a Jeff Lau thing, isn't the final twenty minutes of the first Chinese Odyssey movie Chow going back in time trying to prevent a female character from killing herself. Part of the shtick is Chow narrating the events as he re-does them over and over again. The fantastical language of Ronald Cheng's appearance in Three Kingdom's China makes me recall Chow's increasingly nervous/hysterical narration of his plight of failed time traveling heroics.
6) There's cliche in Asian movies where news or message isn't real until the person with the highest authority/biggest social "face" present says it's real. Cheng's crazy time traveling story isn't accepted as real until Cao Cao's own hype man(!) repeats it word for word. This makes me inclined to think this might be a dig of HK election politics and some news item that was big whilst the movie was being shot. Like some sort of _Ming Pao_ story you vaguely remember reading a few months back... Jeff Lau, however, couldn't possibly be working on that level, could he? Scratch that one off, then?
Wow, this reply is a lot longer than I thought it would be when I started typing. When watching the scene I think #5, 6, and 2 were running through my mind but as I look over what I've just scrawled, I wouldn't be convinced by my own above explanation. I think I liked the scene since it was the least kuso/e'gao humour found in the entire clip, which speaks of actual effort at making a joke as opposed to throwing out of-the-moment "in joke" moments and hoping something in the mess tickles someone's funny bone. That's my two cents. I'm kind of interested in hearing what other people found funny (or not funny.)
BTW, "What Women Want 2011" is probably the class of the recent Chinese yuppie rom-com boom (better than "Go Lala, Go" and "If You're the One"--now those are fighting words!) though I'd personally want to check out 2010 pics "Love in Cosmo" and "Ma Wen's Battle" before making such a bold claim.