One other issue I've found with the Special Offers section. Although you can fill in the amounts, and see a box that says "Guest Pays", that is not in fact what they pay. You do not (or, better stated, cannot) see the AirBnb fee charged to the guest for their reservation. You only see the fee collected from your end. I was in a similar situation, with a guest requesting a discount for a longer term stay (1-3 months). We agreed on a price, I made the "Guest Pays" section come out to our agreed price, and sent it. He replied, saying it was 10% higher than what we agreed upon.
Essentially, you have to calculate the AirBnb fee charged to the guest (10 - 12%, depending on the size of the reservation itself), and work backwards. In other words, take what you want the guest to actually pay, and divide it by 1.12 (its not exact, but close enough).
Although I don't feel its unscrupulous, I do however find it a bit confusing. It made it appear as if I agreed to have the guest pay one amount, then made it look like I was overcharging, since the amount he saw wasn't what we agreed upon, until I fixed it, and resent. IN my eyes, if the box says "Guest Pays", that should be what the guest pays. Sounds like common sense to me, but perhaps in todays age, its a bit....UNcommon.
