I think what you see before you enter dates is the base price for that property.
When you enter your check in and out dates you will see:
nightly price for that period ( in the middle of the season it will usually be higher) + additional cost for additional guests
x as many nights you want to book
+ cleaning fee (optional)
+ Airbnb service fee
= total amount you should pay
So, the best option is to enter your dates and the number of people in your group and then start searching