@Karen691
What @Emiel1 says is correct, and also, if it's Airbnb charging them more, they should really be asking this question to Airbnb, not the host. Technically, the figure for "rate per night x # of nights" and "cleaning fee (if any)" are the ones that the host has any control over. Anything else that affects the final price such as service fees or whatever....it's all under the discretion of ONLY Airbnb.
I've noticed that a lot of guests do not understand this so it might be best if you explain how payment works and YOU (host) have no control over and no idea why Airbnb is charging them that amount.
FYI, all of my guests to date have been international and without knowing exact figures but based on discussions with past guests there seems to be about a 15~16% difference between what the guest pays and my payout amount.
Good luck~