When you initially click on the Billing tab, the display shows your "Current Account Balance" and "Last 10 Transactions".

I've noticed recently that the 10 transactions being displayed are not actually the "last" 10 transactions. In my case, I see transactions dated 01/20 and 01/21. However, when I click on "View All Transactions" at the bottom of the page, and click on the Date column to sort appropriately, more recent transactions from 01/25 and 01/27 now appear.

Specifically, they appear as a "Usage Charge", which don't appear unless I click on "View All Transactions"