There were a number of issues. My understanding is that Netflix was not paying 30% but rather was paying 15% due to their special agreement with Apple. According to the emails, it was Apple's refusal to go below 15% that triggered Netflix to begin testing not allowing payment via IAP. The "voluntary churn", "promotion coordination" and "revenue sharing" offers are from Apple trying to sweeten the pot to keep Netlfix from dumping IAP completely.