I noticed a signifcant difference in "Airbnb guest service fee percentage" when an accomodation is booked for 27 nights or 28 nights (which is considered as a "long term stay"). Testing it on one of my listings it says 15,5% for the 27 nights (or shorter) stay and 11% for the 28 nights stay (or longer). So 1 night can make a huge difference for a guest.
It means (even when no monthly discount is set) a 28 nights stay can sometimes be cheaper for a guest then a 27 nights stay.
(allthough automatically "long term stay cancellation policy" is applied)
Host should also be aware of this when making a special offer.
I had a guest who wanted to book a 28 nights stay, but i could only provide a 27 nights stay. I made a special offer (applying the monthly discount percentage to it by manual calculation), then i noticed the increase in "guests service fee costs" makes it the guest has to pay more in total then for the 28 nights stay.