Actually this estimate is incorrect. If you look carefully, the first mining month is estimated as having a diff of 293 million(!) Our units will start shipping on October 2nd, when we will still obviously be at the current difficulty 149 million.

This is a big flaw of the mining.thegenesisblock.com calculator... The granularity of 1-month in its table of numbers is too coarse to accurately predict the revenue of a miner shipping in the next few days because there is a big difference between a miner shipping on October 1st vs October 30th, but in both cases mining.thegenesisblock.com will show the same revenue!

So to work around this flaw, you have to fudge with the "current difficulty" so that the October 2013 starting mining difficulty starts at 149 million, in which case you see that at 15 BTC our miners are clearly profitable even assuming a 100% month-over-month difficulty increase: http://mining.thegenesisblock.com/a/db4d60faba