Thanks for the answers and suggestions.

The tickets are for my parents and plans have changed so that they would prefer to fly YVR-BOS. Unfortunately there aren't cheap HUP or YUP fares on that route, presumably because its an international rather than domestic route.

Cheapest available revenue fares in F are about £500 and I've got a healthy DC miles balance and want to redeem some of these while DC still exists. So I've booked two miles plus cash tickets in UA F from YVR to BOS, connecting in ORD. Cost per person was 18750 miles plus £125 plus tax.

The ICC quoted £97.80 tax per person. United Airlines UK website and Expedia's UK site both quote a total of £75.80 per person for taxes and charges on a revenue booking in F on the same flights so I asked the DC call centre to recheck the taxes. They are adamant that £97.80 is the correct figure. Looking at United and Expedia's US websites, these both show taxes and charges of USD 226 per person i.e. about £137 per person!

Should the taxes and charges for an award booking be the same as for a revenue booking in the same cabin? If so, is that the same as the taxes and charges shown on UK sites or US sites and why is there a difference between those two?

Thoroughly confused!

Al