Note: I pay only $0.11 per kw, so I see your concerns. Also, difficulty goes up every 10-14 days(give or take) so you will make less and less unless you keep adding hashpower to keep up. On Slushs Pool right now I get 0.01 Btc per block for every 2.10Th. I have been adding 125ghs to each set of miners every month to keep with that payout. I also sell/replace miners with more efficient ones as they come out if I can get them at a reasonable price.