Volume. Let's say their current revenue is R. The 25% promo reduces their revenue to 0.75R, but say they get y% more subscribers. Calculations show that if the

Volume. Let's say their current revenue is R. The 25% promo reduces their revenue to 0.75R, but say they get y% more subscribers. Calculations show that if they can get an increase of more than y > 33.33% in subscriptions, then their promo works.