Google fought to keep the Spotify numbers private during its antitrust fight with Epic, saying they could damage negotiations with other app developers who might want more generous rates. Google’s User Choice Billing program, launched in 2022, is typically described as shaving about 4 percent off Google’s Play Store commission if developers use their own payment system, bringing down Google’s 15 percent subscription service fee to more like 11 percent.

That often ends up saving developers little or no money since they must foot the cost of payment processing themselves. And in court, Google has focused on benefits like greater flexibility rather than cost savings.