No problem. I bought a Platinum contract in January, costs: 5.2 BTC for 420Ghs, available on Feb 15.

Now do the math:
Month 01 : 1.4 BTC (at most! With a few days to go it's 1.25 actually)
Issue, is of course rising difficulty. In general that difficulty halves revenue every month. Apply that to the remainder on the year contract:
Month 02 : 0.7 BTC
Month 03 : 0.4 BTC
Month 04 : 0.2 BTC
Month 05 : 0.1 BTC
Month 06 : 0.05 BTC
Month 07 : 0.0125 BTC
Month 08 : 0.007 BTC
Month 09 : 0.004 BTC
Month 10 : 0.002 BTC
Month 11 : 0.001 BTC
Month 12 : 0.0005 BTC

Total over 12 months : 2.877 BTC
Cloudhashing charges a whopping 10% fee, makes the total 2.58 BTC.

Lets see, I invested 5.2 BTC, I will make only half that.
Actual revenue: -2.6 BTC !!!!