Eu "escalonei" o "Posso usar meus Avios com as cobranças extras de peso?" pergunta para flyertalk. Esta é a resposta :
No, not directly, though if you have a BA ticket you can use Avios to upgrade to a higher cabin to gain the increased baggage allowance, subject - of course - to availability. In some situations this may be a good idea.
But you can't currently use Avios to directly pay for luggage. However this is a study going on at the moment to greatly expand the use of Avios, to include paying for seat fees, luggage and other ancillary services. Buy on Board is an example of this happening.