Why do I need two verification codes to change my phone bill?

In order to ensure the security of real estate information. Mobile phone dynamic password is enabled. If the phone bill amount exceeds the preset limit, the step of SMS verification is required. In order to ensure that the information operation is a personal operation, paying more than 200 with Alipay requires SMS verification again. China Mobile is a mobile communication operator based on GSM, TDD-LTE and FDD-LTE networks.