Taxes from HKG
 

I've just tried to add a return leg HKG-LHR-MAN to a BAPP 2-4-1 booking and been quoted ~£240 tax/charges pp for the one-way leg. That sounded a lot to me so I checked BA.com and, as a standalone leg, the tax/charge shows as £70pp. I then looked on the Matrix/ITA site and taxes show as HKD700 - again ~£70.

The BA agent insists that her figures are correct, that its been double-checked and that BA.com is wrong.

Does adding a return leg to an existing booking affect the charges in any way?

I always thought a return booking was effectively 2 x one-ways for tax purposes. I've asked them to break it down because it doesn't seem right but they're insistent their figures are correct. Anyone else had to dispute taxes and is it likely BA's calculations are wrong?

Taxes/surcharges for a round trip are based upon the initial departure point, in this case the UK. The taxes/surcharges are not the sum of the taxes/surcharges for two separate one-ways. See:
https://www.flyertalk.com/forum/29147378-post409.html
https://www.flyertalk.com/forum/29147427-post411.html
https://www.flyertalk.com/forum/brit...upid-head.html
https://www.flyertalk.com/forum/brit...-question.html

Thanks for the replies. Done the round trip on Matrix and taxes showing pretty much as BA say. Good to know for the future if not exactly the result I was after.

Taxes, fees and charges for EDI-LHR-HKG return in F using an AMEX 2 for 1 were £1324.90. That was booked online in a single session last spring so if you are in that ballpark it is probably about right.