You didn't accounted for maintenance fee. Taking that in account, you will be earning only 0.25% per day on your investment. I calculated this on the basis of investing $200 at current price of $1.2 per 10GH/s. I put these parameters on coinwarz.com website and it shows that I will earn $1.26 per day. Now maintenance fee is $0.0035 per 10GH/24hr. So for 1 day it will become $0.70. Our total profit will be $1.26 - $0.70, i.e. $0.56 which is 0.25% of our $200 investment.