To get the thread back on track;
Take an average of 800 hours per year;
800/12 = 66.6 hours per month
if your pay rate is 70.5 then budget on 4700 euros gross per month. In the summer if you do 100 hours, then bank the 33.3 hours of extra block pay in order to not be down on your month off of zero hours.
its not rocket science
