iTunes Account Purchase History.Gift Cards Redeemed

I have a concern with itunes Account History. When I view account history of itunes I only see purchases, itunes does not shows gift cards redeemed. The itunes main page shows an _account balance which is great_, but when funds are taken out and you feel there was a double charge,the account history does not show that gift cards were redeemed (credit to account), only purchases, so how does a customer, balance their account