I was in doubts about price of "Single". So I've made guess about bitcoin network hashrate.
Hashrate[time] = K*time + B
7 days moving average points:
24563.197 at 15-February
74692.342 at 30-April
![](https://ip.bitcointalk.org/?u=http%3A%2F%2Fi1273.photobucket.com%2Falbums%2Fy412%2FVezunchikPhotos%2FNetworkHashrate_zpse9df4750.png&t=665&c=pctEcdnYIo9Cxg)
K = delta Y / delta X = (74692.342 - 24563.197) / (4-1.5)*2 = 10025.83 Ghash per 2 weeks growth.
B = 24563.197 - K * 1.5*2 = 24563.197 - 30077.5 = 5514.29 Ghash base.
This order must be ready in 2 months (or even earlier if there will be many refund requests from BFL customers - every refund will move order up in the queen).
So income will be
in 2 months hashrate will be 10025.83 * 6.5*2 + 5514.29 = 124821.487
3600 * 60 / 124821.487 = 1.442059411 BTC per day or ~52.7784 BTC per month
in 3 months: 10025.83 * 7.5*2 + 5514.29 = 144873.145
3600 * 60 / 144873.145 = 1.242466297 BTC per day or ~45.474 BTC per month
in 4 months: 10025.83 * 8.5*2 + 5514.29 = 164924.803
3600 * 60 / 164924.803 = 1.091406488 BTC per day or ~39.9444 BTC per month
After this, I think any extrapolation has no sense. So you will have at least ~138 BTC income in short range (I think more, because constant linear growth of network hashrate is impossible).
And constant, but smaller income in long range perspective.