The thing is we shouldn't be going through this de-crediting/re-crediting hassle in the first place!
We should have the freedom of choosing the card that we want to use, up until the point of boarding or at least the point of Check In.
BA requires you to have the same FQTV card on your BP as in your PNR, only then will they credit the points accordingly. Otherwise it will just go to the number that is in your PNR.
Sometimes we just can't decide which program to boost, if we are members of multiple programs in the same alliance.
I know, I know... choose one and stick with it.... but what if that's not our choice or not always possible?
And what if you have multiple flights in the PNR and you want to use one card for flights 1,2 and 3 and another card for flights 4 and 5?
You have to call and change the number on your PNR in between flights?
Mate... seriously....
Who was the BA brilliant master-mind behind this decision?
Unfortunately it is often forgotten (by people on here as well as at the airport) that we are paying customers, often paying out of our own pocket, and that we're not given tickets by charity.
James Hillier... sort it out, mate. Get some work done.