There is no feature to take away sales in Nats. However, there is a feature to add sales as you have pointed out. I seriously doubt programs are just willy nilly with this feature. I mean if we're not making any money off your traffic, I'm certainly not going to give you extra money.

Most programs do have this feature...I'm almost positive that mpa has this feature. I know that ccbill does too because you can assign a member to a certain affiliate - so its the same thing.