@Charl2838
The host job is to set the maximum number of people the place can host and the price.
This number is a real maximum for insurance reasons and sometimes legal reasons (decent place).
The traveller host is to enter the right information about the group.
What dates? (price can change with dates and number of nights).
How many adults?
How many children?
How many babies?
How many pets?
So the right price appears.
And the right information is written in the contract (reservation).
If you read your Airbnb reservation, it is written :
1 people for X price and dates.
So now you have to update the contract with 2 people and Y price and dates.
It is the guest duty to give all the necessary information about the group to check the place is suitable for its needs.
The best is to do it before booking with an request for information (contact host button) instead of a request for reservation.
You assumed that it was the same price for 1 or 2 adults.
Some other travellers assumed is it the same price for 1 or 4 adults, 2 children, 1 baby and 2 big dogs (real case).
Surprise!
Hopefully, it is not on a legal point view and host opinion.
As far as i am concerned, it is the same price for 1 or 5 people.
The all pay for 5!
If there is a mistake (sorry, my mother-in-law wants to come with us in Paris), 5 instead of 4, it is easy to correct.
It makes sense to have a price per people for big houses (6-8 people).
I would have set a flat rate for a studio as it is the same cleaning and electricity and heating for 1 or 2 people.
Only the water is different and can be included directly in the price with a base of 2.
This is my point of view and hosts are free to chose their price depending if they prefer to have small or big groups, duration of stay and season.
In your case, host prefer to have 1 people and did an attractive price for 1.