每更新一次itunes store account的信用卡資料就會試刷嗎?

[tibullus]

我是新購買iPhone 3GS的用戶，
剛剛嘗試更新了兩次iTunes store account當中的信用卡資料，
就是刪除與新增的動作，
我就會收到信用卡中心用簡訊傳來，
我剛剛已經經由國外刷了一筆32元的資訊，

想請問一次這是否正常呢？
我是有聽說有試刷的狀況，
但沒有遇過只有修改過一次就試刷一次的狀況

我的信用卡是中國信託

我有設定只要有刷卡記錄就請他們發簡訊通知我

在麻煩各位大大回覆一次我的疑問囉

感恩

[tibullus]

上了以下網頁，看到了相關訊息，如下：
Link:http://www.apple.com/support/itunes/
Click this item:iTunes Store Account and Billing
open the lists, and choose this event:Payment methods
About credit-card authorization holds

Introduction


As with many other merchants, the iTunes Store places an authorization hold on your credit-card account for the approximate amount of any purchase you make. Similarly, if you update your billing information, the iTunes Store will place an authorization hold on your credit-card account, usually in the amount of 1 USD, to verify your account information.

How To


You might see such authorization requests on your online statement. These requests are not actual charges; they are tests to confirm that your credit-card account is active and has credit available to accommodate transactions. Authorization holds are removed by your financial institution shortly after your purchase clears. The amount of time it takes to remove authorization requests varies by financial institution.
To review the actual charges on your account, you may review your iTunes Purchase History (you will be prompted to enter your iTunes account name and password). Your Purchase History will display your most recent purchases first. To view details of any purchase, click the arrow to the left of the order date.
If you have questions about the way your financial institution handles authorization requests, please contact their customer-service department.