No, there are no additional fees when using Touch 'n Go eWallet to pay for your Apple App store and/or iTunes purchases.
Find out more on exclusive promotions and new features, such as subscription management and billing history, in Apple Zone.
You can click on Apple Zone in the main page upon opening Touch n' Go eWallet.
You can also enter Apple Zone by clicking 【More】 at the Touch n' Go home page and find 【Tickets & Entertainment】 and click on the Apple icon.
Visit the Apple Zone FAQ page for more information.
Below are the articles that may be useful for you :
What is Apple auto debit with Touch ‘n Go eWallet?
How do I check my purchase history in the App Store and iTunes Store?
Where can I find more about Apple auto debit with Touch ‘n Go eWallet?