I don't have my cards in front of me so I'll have to re-read this one and get back to you.
It would read more clearly like this: 'Use this card to make up to, but no more than, 5 re-rolls'. So the 'up to' part means you can make 5 or less. Yes, this would be in addition to your Cunning score.
If you're playing with folks who are that serious about their gaming, you should perhaps be playing Game of Thrones I would just use the dwarf cards to bid.
