The advanced deposits report are receipts taken in for bookings where the Arrival Date is either TODAY (and check in has yet to occur) or still in the FUTURE. Thus, this lists all 'current liabilities' where you have taken monies but have yet to provide the service.
If there has been a receipt of payment (either via an online booking or an 'apply payment' event), and the booking or group booking has an arrival in the future, that amount will appear on your Advanced Deposits Report.
When the booking checks in, any payments received for that booking - which had been listed - now disappears from your Advanced Deposits Report. Thus, checking in a booking clears the amounts that had been listed as 'Advanced Deposits'.
Here is an example:
On February 10 you take a booking for March 9 and your policy is to take two night's deposit, so you take $200 ($100 per night) and 'apply payment' to the booking. Your Advanced Deposits Report will list $200 from February 10 forth.
On March 9, the booking is checked in. At this point, the Advanced Deposits Report no longer shows the $200. It has been removed from your Advanced Deposits Report because it is now 'governed' by your booking. The folio now governs the $200.
Following this example, by March 10, the room rent for March 9 would have posted at $100 and thus, the $200 'advanced deposit' has now been reduced to $100 and after the second night's stay, the 'advanced deposit' has been used up entirely.
This is key to understanding the Advanced Deposits Report.