Power usage is *everything* when it comes to ASIC. If you think it's not, you have no grasp on the economics of mining.
Please explain your economics of mining. By my calculations power usage at this order of magnitude is pretty much irrelevant compared to price.
Take a BFL Single, 60 Ghash/s, 60 W. The miner costs 1299 USD and will use 1.44 kW/day. 14.4 cents a day at 0.10 USD/kWh. You can run this miner 24/7 for almost 25 years before you have spent the same amount for power to run the device that you paid for the device itself! There may even be better miners to buy at a lower price in 2037, making it obsolete before the owner has spent more on power to run it than on the device itself. If the device is still working. (How long is your warranty and what is the expected lifetime of a BFL Single, btw?) Hardly anyone will ever pay more for the power to run the miner through it's lifetime than they did for the miner itself.
My simple math shows that
power usage is almost
irrelevant for an ASIC miner. Price per Ghash produced throughout the miners lifetime will almost certainly always be dominated by the initial investment, not power consumption.
Price per Ghash/s is the important factor.
Is my math wrong?
No, just your assumptions on difficulty. I don't expect any of these 60 GH range ASIC products to make even $1000 in 2013 alone. By design, difficulty will always bring the cost-to-mine very close to power costs. When it catches up, power costs will be all that matters. Until then, delivery dates before it adjusts are the key importance.