Originally Posted by LondonAndy

Yes, the proposed change will be very welcome - I got caught out by this a couple of years ago (as well as not being able to upgrade unless both outbound and return are in the same class). Since then I haven't bothered taking the shareholder discount given the relatively small element that the fare often represents against the cost of the ticket given all the fuel surcharges etc., so that if I did want to upgrade at a later date I may be able to.

All BA need to do know is remove all the surcharges (rather than tax) and lump them in with the fare, so that you get the discount on them too