I know what you mean but that's not exactly what I wanted to do.
Example
I set up cart rules for 3 different products offering a 0.35p discount in value on each of them. To access this they need a promo code as the offer is restricted to a group. Someone decides to buy 3 off of one product, so the calculation is:
(3 x 5.35)-(3 x 0.35)=£15.00
It doesn't apply the discount for each one they add to the basket.
Thanks