Didn't you find the exact figure in the FAQ that the fee is $0.001 Per GHs. Notice it's in dollars not BTC.
email:
"The fee will be implemented in 1 week, which makes it November 8th 2013.
The maintenance fee is estimated as $0.30 / kW*hour:
$0.17/kW electricity cost + $0.09 data centre upkeep + $0.04 hardware repair/maintenance.
(The power consumption of 1 GHS is 1.5W per hour)"
Including:
- hashrate of 2,000 GH/s
- for watts it will be 3000. As stated 1.5W per 1 GH/s
- fee of 0.30 kWh per GH/s