You agree to keep accurate books and records related to your development, manufacture, Distribution, and sale of Royalty Products and related revenue. Epic may conduct reasonable audits of those books and records. Audits will be conducted during business hours on reasonable prior notice to you. Epic will bear the costs of audits unless the results show a shortfall in payments in excess of 5% during the period audited, in which case you will be responsible for the cost of the audit.
Ironically, this is something that is bothering the appellate court as well if you read between the lines of their judgment[0].
They gently criticize the district court for both saying that developers should be able to link and sell outside the app while simultaneously saying that it’s undesirable for Apple to audit developers because it’s too cumbersome.
But the appellate court isn’t meant for do overs, just for when courts have erred in a significant way, so they only gently lament this, instead of doing something about it.
0: https://cdn.ca9.uscourts.gov/datastore/opinions/2023/04/24/2...