This seems about right (although a bit expensive) for a main dealer service. Although it is illegal for them to insist that the service is done at a fiat dealership to maintain the warranty. As long as the service is to at least the same quality and the parts are of similar quality also - they can not insist that fiat do the service (I was working in the motor trade when this came about and is certainly true for fords and I can not see fiats being any different)
Some people will prefer to see the dealership stamp in the book - but it is up to you.