The time estimation is based on the number -- just based on the rate of increase, I'm probably not far off. The number, though, is complete guesswork, purely based on discussions I've had with people about BTC's current rise; no evidence in the least. I have little enough to lose here that I'm willing to go by my gut on it; if it turns out I'm wrong, I won't be losing any sleep, which is always nice.
That's a large part of why I'm thinking it'll happen. There's something "different" about $200 when people talk about the rise of Bitcoin; that number just makes people uncomfortable. I don't think it'll rise much beyond that, this time around. (Though I do think that the eventual value of BTC will be much, much, much higher, years down the road.)