Is there a way to determine the amount of commission generated by an airline ticket sale by a travel agent just by taking a look at the ticket sold? Sometimes the final price displayed on the ticket itself does not correlate to the amount actually paid for the ticket. Sometimes the price printed on the ticket is the actual amount charged to your credit card, but, in many cases, the travel agent gives you a rebate cheque.

Example: British Airways YYZ-LHR-ALA-LHR-YYZ
Price on the ticket = CAD$3580.98
Amount charged to card = CAD$3580.98
Rebate cheque = CAD$2510.98
FINAL PRICE = CAD$1070.00

What is going on under these digits??? How much is my travel agent getting for selling this???