If you configure taxes for Expedia in myfrontdesk - they should totally match the tax type and amount on Expedia Extranet.
To configure the tax for third party sources please consult this Knowlege Base: Applying Taxes and Fees To Reservation Sources
To configure the tax for Expedia on Expedia Extranet - please contact your Expedia Account Manager.
Issue with taxes for Expedia Collect reservations
We have recently identified that there was an issue for Expedia Collect reservations: even if your Expedia account is correctly configured as Tax Inclusive, it's possible that this is not properly configured for Expedia Collect reservations.
Solution: Please contact your Expedia's Account Manager or Support and ask them to set the taxes as Inclusive for your Expedia Collect bookings. This setting is done on the Rate Plan level. If you need our assistance with this issue, please contact our support team.