What is the App Store Small Business Program?

You enroll as the Account Holder: accept the latest Paid Applications agreement in App Store Connect and list every Associated Developer Account, so Apple can add up the proceeds of related accounts. The new rate applies fifteen days after the end of the fiscal month in which Apple approves your enrollment. If you cross the threshold in a year, the standard commission applies to future sales, and you can re-qualify the year after your proceeds fall back under $1 million.

For subscriptions the program changes less than it first seems. Without it, you receive 70% of the subscription price (minus taxes) in a subscriber's first year of paid service, and 85% after the subscriber has accumulated one year of paid service. Members of the Small Business Program receive 85% from the first billing cycle, whether or not the subscription has reached a year of paid service.

Google Play sets its service fees separately and updates them by region, so read its service fee page for the current rates rather than assuming they match Apple's.

Sources: Apple: App Store Small Business Program · Apple: Auto-renewable subscriptions · Play Console Help: Service fees