YEs--I found the discrepancy before the guest left and began my questioning then. No extra guest. The son (who made the reservation) DID ask to extend his parent's stay--leaving me out of that request. The son told me he made the request and I clicked on accept when air bnb sent me notification of said request.
I did not realize until after the booking was made that I could check the 'breakdown'. DIdn't occur to me that my minimum nightly price would be overridden somehow.
And yes--I have a minimum amount per night set. The amount charged for those six nights was 35% below that minimum.
And no, I never agreed to any 20% discount for higher spot in posting (another thing I never heard of, lol)
Yes, I'm a newbie. Less than six months. Mom and pop one bedroom in home rental. Income to help our retirement.