Only say that the price of extra guest is on the website of airbnb from the beginning.
And you can also see the apartment only accommodates three people.
The only thing that was a favor for you accommodating two guests more.
Regarding the time of departure , it 's nothing personal , but in the world there are very not good people who pay for two people and put 4 in the apartment. I needed to check that the other two persone were gone to the apartment.