Originally Posted by
Globaliser
I can't reconcile these numbers to the ones you give, because you should be able to upgrade with BA Miles from the $2,100 ticket. You'll pay fractionally more than that, plus the miles. So I don't know where your $4,448 figure comes from, nor your $11,079 figure. No WT+ should cost as much as $11,079, even if you are upgrading it with miles. Something is wrong there.
I think the OP is looking at the price of two tickets. If you double your figures of $2100 and $5500 you get approx what the OP is quoting.