On the confirmation email, under each passenger it itemized the taxes as follows:
USD FARE 00
TAX-USD 5.00 YC
TAX-USD 75.68 XT
USD TTL 80.68
Now it gets even stranger, when I checked the reservation online yesterday it had total taxes paid as $161. I just double checked again this morning and the total was back to the $242.04. It hasn't appeared on my credit card yet, but I'm pretty sure it will be for the more expensive amount.
Oh and it's three of us flying BOS-YUL-CDG