Under CALENDAR I was able to reach the PRICE CALCULATOR. I tested from 1 to 4 guests and concluded AirBnB adds the extra guest fee to the base nightly price, starting from the first guest.
E.g. nigthly price = $100. Extra Guest = $25
1 night for 1 person = $100 + $25 x 1 = $125
1 night for 2 people =$100 + $25 x 2 = $150
1 night for 3 people =$100 + $25 x 3 = $175
1 night for 4 people =$100 + $25 x 4 = $200
and above 4 I would need to reset the reservation, review the prices, etc.
Does it look correct?
Thanks.