Any postdoc in Italy?Hello...

Any postdoc in Italy? Hello all, I am a MC postdoc in an Italian company within an ITN network since 4 months ago. I am having some troubles since I do not understand why my net salary keeps changing every month in a big amount, and my boss says that it is impossible to calculate how much I have to earn each month since the taxes vary monthly (that are already around 50%). If there is somebody else working in Italy I would appreciate your experiences in this sense and about the taxation of the mobility allowance. Thanks a lot!