We were a party of 6, but I was meant to stay in the flat only one night, with my in-laws taking my spot on the following days (so max 5 people in the flat in any given night).
I admit I was not clear on this, however when we asked Angela she did not allow the swap and my father in law had to sleep elsewhere.
The host also asked for extra payment for my mother in law (on the ad it is mentioned extra payment for the 5th guest, but never more than 4 people slept in the flat).
We payed lodging taxes for me and my wife even though as residents in Milan we should not.
Finally the host suggested on the phone not to even think to try and sneak in extra people, I honestly did not think this comment was appropriate.
Ended up leaving one night early and get a hotel for the rest of the stay.
In fairness the place was nice and clean, I would just recommend to be extra careful and agree beforehand on what you owe, so to avoid unpleasant surprises like ours.