He never published it. It's an estimate based on FC's old balance sheet, where he had listed the total cost of making all the hardware. Then I figured about how many TH he'd produced based on his total sale profits divided by price/TH, plus the known farm size (~50 TH).
The USB sticks were a complicating factor. Obviously it is a rough estimate but it is better than nothing.
If that is true, ASICMiner is probably worth less than 0.5 BTC/share. They'd be better off buying Cointerra hardware than making their own, considering Gen 2 is at the 55nm node and probably won't be more than 4x faster per chip.
It's not fear, uncertainty, OR doubt. It's math and logic.
Obviously you are new to investing.
You cannot say it's a rough estimate than claim it to be "math" and "logic" later. Until you have all the financial sheets backing up your math, it remains as "a rough estimate". I would suggest taking a look at
CoinTerra's thread before saying they're "better off buying CoinTerra's hardware."