Doesn't take into account future price rise of BTC. If they are worth $500 in a years time then is your hardware still profitable? By the way $0.087 /kWh is low, it's $0.28+ where I live...
If they are worth $500 why bother investing in GPUs and not buy BTCs?
Not all of us area able to put mass amount of instant cash into hopes and dreams. A small amount of electricity cost is a lot easier to cope with. haha