Another thought. The combined City plus State sales tax in many Washington State cities is close to 10%. Maybe you did not actually fill in the deduction amounts in the deduction areas of the form. This would cause a tax due of almost 10%.
Just to be sure. Each deduction area has 3 items to fill out:
a place to write the amount deducted (enter the entire AirBnB gross receipts amount)
a place to choose what kind of deduction you are claiming (for AirBnB receipts, you choose “Other”. It’s the last choice on the list)
a place to explain the Other designation (you enter a statement that AirBnB collected and paid the taxes).
Fill all 3 items in each section of the form that has deduction field. For sure the B&O section has deductions, and the State Sales and Use Tax section. As I said, I can’t remember if the Local Sales and Use Tax section has places to report and deduct the AirBnB receipts. Put em' in if it does.
Also, do not report any AirBnB receipts in that Transient Lodging section, if it shows up later in your form. You already reported these receipts in previous areas of the form, and AirBnB already paid the taxes.
I’m not a tax professional, so if things don’t look right, phone the DOR help line during business hours.