@Anita274
I use it occasionally, and Airbnb has always passed it through entirely, with no commission or other deductions. If the guest pays it prior to arrival, Airbnb pays it to you combined with the regular payment. If not paid prior to check in, it is paid to you several days later.
But before you can request funds, you must select one of 5 or so options describing what the charge is for. I always choose "additional services" (or something like that). They might charge commission on other options, I don't know.