FPGA
Investment: $2000
FPGA's: 5
Total Mh/s: 950
Monthly power cost at $0.12 for 45W: ~$4
BTC Payout: 0.9762 BTC/Day or ~30 btc/month
USD Payout at $2.70: $81
Monthly net revenue from $2000 investment: $77
Your BTC/month is almost 50% higher than the real earnings at these difficulty levels. They'll fall at the next change, but not enough to earn 30/month at 950 Mh/s. It seems to me that it won't fall this much unless the price falls even more.
You're right, its .65 BTC per day on the FPGA setup and 1.83 BTC per day on the GPU setup in the example at current difficulty. Maybe his calc uses a pool hopping formula to get the numbers?