BPF & Postage Refunds

se2020

If a buyer purchases from 2 of my listings and I can post both items together for the same price then I refund one lot of postage.

Firstly,  I am assuming,  if I send a partial refund of £10 (for any reason) then ebay will also refund the corresponding amount of the BPF?
So the buyer would recive a £10.40 refund?

Secondly,  if that is correct, 
With the BPF not being charged on the postage amount originally,  does the BPF part of the refund not get applied if I select 'postage discount' as the reason for the refund?

Basically,  If I wanted to refund a buyer £3.39 as a combined postage discount could I just refund £3.26 as a 'general discount' and expect the buyer to receive £3.39 from eBay?

savergrant

I don't think it makes any difference what reason you enter, I think that is just what eBay tell the buyer. I've just noticed that a couple of combined postage items I've sold have refunded part of the BPF.