Here is the transcript itself:
[COLOR=#000000]"The four that were revealed at the end of season three," Douglas tells SFX on set in Vancouver, "are what they are, but they're one-offs. They're the original Cylons. Hundreds of thousands of years ago, when there were 13 colonies on Kobol, 12 went that way and one went that way to find Earth - or create an Earth - and that colony was actually Cylons. They're individuals, there's no multiple models. The seven that we know are a different kind of Cylon that came much later. They're probably ten, 20 years old, born out of the metal machines that fought back 40 years ago in the Cylon Wars of the 12 Colonies. So they're essentially like the gods. And we were on the new Earth, and destroyed that and came back to the 12 Colonies to rejoin humanity to find out the cycle of time. Why do we create a world and destroy ourselves? Why does humanity do that? And why do we as Cylons follow that path to humanity? So we sort of turned off the Cylon part of us and went and joined the humans. They don't know we're Cylons and we didn't know until we started getting closer to Earth - what's when we started hearing the music at the end of last season and get woken up to the fact we are."[/COLOR]
Now, we also know that Three has said only 4 are in the Fleet.
Following the idea that 1 colony (Cylon) went to Earth and the rest went to the 12 Colonies, I wonder if this accounts for what Three said...
4 of the Final Five went to the Colonies.
1 of them found the Cylons.
Ergo, Three says 4 are among the Colonists, and 1 is, presumably, among the Cylons.
So, the division between the 4 and the 5th is a repetition of the pattern within the Cycle of Time itself.
Maybe this holds the key to Cylon Evolution. The Fifth, finding the Toasters, intended to start a "new" race of Cylons in its own image, leading to the Skinjobs, in the same way that the original 13th tribe established Earth and evolved into the "final five" type of Cylons.
Something may have gone awry with its plan. The Cylons, like Number 1, turned on it and set about their own plan - the destruction of humanity itself.
Also, the Four heard the music, because they used it as a signal to reactivate their Cylon consciousness as they neared Earth. Presumbably the reason, then, the Fifth, if we've seen it, didn't hear it is because it is still aware of who and what it is. It never turned itself "off" in that way, so it didn't need the music.
So, the question remains is whether or not the Final Cylon, assuming it found the Toasters, left them. If so, then that would, in fact, account for the discrepany in the numbers 1 - 6, 8. Maybe Number 1 is, in fact, lying about the numbers, that is, the Final Cylon is "Number 1" and the rest follow in line after it. Cavil has simply coopted the number for himself, perhaps. At the same time, Three may think the Final Cylon is among the Cylons, but because it left (maybe in a different body than the one that it was using when it first met them), she simply isn't aware that it's gone.
On this view, the Final Cylon could well be the Virtual that we've seen, or it could be one of the physical characters. I still lean toward Dualla, if it is a physical character, but, if not, then IMO, the next most likely candidate is that it is the Virtual model we've been seeing.