I agree with Skrubalov. For those who don't know or don't care about the details, the bitcoin price is always following the difficulty. Furthermore, the introduction of new technology always boosts the prices higher (see the timeframe when the first ASICs came into game by Avalon). That said, i can "almost" promise you that the bitcoin price will not stay at $140 - $150, it will climb even higher. So when you draw the line after mining for one month, you will get almost the same amount of money. Right now, with the difficulty of 65 million, the price of the BTC counterbalances marvelously the difficulty, making the ROI exactly 3 months for one full klondike miner together with chips! Not a single day more than i have calculated back in May while starting the Group-Buy.
So my advice is DON'T PANIC! Never panic, because it doesn't solve anything. Everything is going to be fine and i promise i'll do my best to make it be ok for you guys.