You may be able to check the transaction fee charged to your order from Order Details
Seller Center > My Income > Released > Filtering Dates/ Duration > click on the amount to view the transaction and order details.
You will be able to have a view The Order Details like below:
Or you may get the exported report from My Income > Released > Filter duration needed > Search > Export
Under the report column of Transaction Fees will indicate the Seller Transaction Fees in Order Level