My country has a per night fixed amount tax, AirBnB collects this and remits correctly but ChannelBridge cannot account for it automatically (that I can find anyway-there is no way to calculate it from the rate!)
If Airbnb's remitting the tax themselves, channel bridge should be able to access the total amount for that tax and populate it on the Guest Channel Fees section of the Charges tab on the booking in OwnerRez.
If you're not seeing that, send in an email to the helpdesk with the booking number and the channel bridge file you imported and we'll look into the issue.