You may see a lack of data at the start of months due to a billing switchover.
There is often a delay of up to 4 business days during which no bills for the new month are delivered. Also note that while bills are usually finalized 4-7 business days after the close of a month, additional costs may appear as late as 14 days into the new month.
This is due to the invoice closure period for the previous month where all costs for the prior month are finalized.
Expect to wait up to four business days for cost at the start of a new month.