If difficulty is 57% more, then average time per block is 57% more. So if it took 1 day to get a block before, now it takes 1.57 days. Thus, your payout per day is now 1 block / 1.57 days or .636 blocks/day. Or in our case, payout was 1.146 BTC per day, it is now 1.146/1.57 = 0.73 BTC per day.
In the future it'd be good if you didn't insult before you knew you were right...
Not getting into the debate over whether the multiple topics or negative attitude is correct or not, I do have to defend his math, as he clearly states at the end "multiply by 1.1 for a 0% fee proportional share pool" which gets you up to the 0.73 that everyone else calculated. He just went the roundabout way of saying it, showing the lowest possible outcome (PPS, deepbit)