It's probably based on the amount of change down the back of Tim Cook's sofa!i am not disputing they can issue a fine as they see fit or the amount BUT the global sales they base it on.
why? how do you justify that number being used?
It is silly that they fine them based on worldwide sales when the issues are/have been localised by Apple.
Apple's response takes the biscuit somewhat though:
“As our appeal will show, the EC is mandating how we run our store and forcing business terms which are confusing for developers and bad for users.”
Er, Apple are the one laying out the business terms for collecting commission on external payments which bypass its own systems and cost them nothing to process. They could do what they did in the USA and get rid of all fees on external payments and avoid the fine altogether but once again choose to dig themselves a hole then complain the EU sold them a dodgy spade.
Apple have every right to charge a commission on their own systems (even if it is too high) but payments taken outside its walls they have no right to any percentage of. Devs are already paying Stripe fees on them.