old sales should still be honored under the original agreement as those were the terms when you sent any old whales that continue to spend, changing the terms to say you have to keep sending a minimum amount of current spenders for old sales to be paid is horseshit as many people stop promoting programs after a while if they find something better, guess the new questions will be "What's your definition of Lifetime?" and then "What will be your definition of Lifetime be in a year or 2?"
http://dictionary.reference.com/browse/lifetime glad I never promoted that shit