G/Girl....
The 900 hours are purely flying hours - from leaving the gate until arrival. So take a typical 3 sector day - AMS there and back followed by AGP n/s. You would probably only do 5 hours flying but your duty hours would probably be around 9. We are only allowed to do 900 flying hours per year, but believe it or not, 2000 is the max duty hour restriction.
So when you are doing your hourly rate calculation, bear in mind that its the duty hours that count...