@Evan36
I charge an additional amount of $15 per guest after two.
There are the deliberate issues where the guest is well aware that a third guest is going to cost extra and figures they will book for two and work out some advantageous solution for the third (and possible fourth) down the track. You no doubt get those as well Evan!
But when it comes to my base pricing amount, guests don't think it matters whether they book for one or two. Airbnb prompts them at the time of booking to declare the numbers and names of guests who are coming but, the guest doesn't realise that all guests need to be registered in case of any issue.....and Airbnb don't spell this out to the guest forcefully enough. I know because I have just been through the booking procedure, and as a host I take particular note of what the guest goes through! I am just prompted to put in the numbers and names of accommpanying guests who will be travelling in my party! But it's not an obligatory part of the booking process!
Guests are finding the Airbnb site is becoming more difficult in all aspects from searching to the review process, so if they think something is not actually attached to the booking process and will not affect the price, they just ignore it!
A year ago we didn't have the complications on the platform that we have now.....we can't even see a reference calendar in our guest message stream any more.
I still feel your issue is related to your pricing.....however I could be wrong Evan....have been many times before!
Cheers......Rob