Does it say in the Airbnb, what rate they will charge you for electric? It seems like for 8085 units, they are charging you 7 baht per unit instead of 4.5-5.
For a one bedroom condo/apartment, that usage does not seem possible even if you ran one or two ACs 24/7 the whole 4 and a half months, unless maybe you were doing it with all the windows open. It's possible this AirBNB owner just sends the same before and after photos to all long term tenants, if you didn't check and verify the meter in person, yourself.