Why is my invoice larger than usual?
For Pre-Paid customers only: Most of the time, charges will match up with weekly spend. However, when activity on your account affects your required balance, you may be charged more or less than the spend for that week. You can also review that week's invoice in Billing History.
The other occurrence where an invoice is larger than usual is if you recently paid a previously posted invoice prior to the current invoice being created in. In some cases, the invoice creation window does not account for the paid invoice.