You're off by an order of magnitude there. If 90% of billings were commission-free, that means $110 billion had Apple's commission applied to it. 110 * 0.3 = 3

You're off by an order of magnitude there. If 90% of billings were commission-free, that means $110 billion had Apple's commission applied to it. 110 * 0.3 = 33 billion of revenue at most, or 16.5 billion if we use the 15% commission.