Continuity error (spoilers)

So someone asked this question in 2010 on this films message board, but the person who answered didn't really answer the question (no offence intended)

I watched the international version as I know these scenes were altered for the american release, but to which extent, I'm unsure.

---Spoilers---


So we know that Zhou Yu can impersonate other peoples hand writing (a scene of him showing his wife her handwriting). He tricks his friend and sends a falsified note that suggests that the two admirals are planning to mutiny/are disloyal. So far so good.

Now at the same time Zhuge Liang is tasked with getting 100,000 arrows.

Both of these tasks are taken very seriously in the movie, whereby they agree if they don't fulfil their side of the bargain they die (no jokes amongst soldiers etc.) It is silly but it adds to the tension of the two strategists. Even if they reneged on that agreement, it would still be a massive failure.

On the boats Zhuge Liang says no one knows about the plan (maybe he misspoke, or just meant everyone but Zhou Yu)

They don't collaborate, its like each strategist has a challenge.

So here's what I don't understand (I've watched the 15 minutes before and after hoping I'd missed something). But Zhuge Liang intentionally lets a boat drift over to Cao Cao, which directly results in the beheadings of the admirals. How would he know to do that?

Secondly, the falsified note says, the admirals will provide arrows. Again, this indicates collaboration.

Lastly, impersonating someones handwriting requires a sample. To replicate something you need an original. To make it worse, its not just the same handwriting, but the same grammatical errors!? That requires intimate knowledge of that persons command of whatever written language.

I know the film is John Woo and it's essentially dynasty warriors, but still - bothered me immensely. My guess is that they didn't want to show any collaboration so it builds up tension in the film, because you don't know about either of the plans yet. In any case, even when they succeed, they ask each other if they succeeded which is a moot point because one cannot succeed without the other.

Sorry for the wall of text, and the next time I'm launching a naval assault with archers and I've forgotten ammunition that arrow idea was awesome.

What are your thoughts?