The Revenue Comparison chart is a forecasting tool that:
Shows you how much money is owed to you in the coming months or years
Automatically updates when payments are received
Here's an example:
If you have a payment due next month, the graph will show that payment amount as revenue on the due date. But if your client pays early, and you receive that money this month, the graph will automatically update and move that revenue, originally showing on the due date next month, to the paid date this month.
If you're looking at today and into the past, the graph is tracking received cash. The revenue is showing on the date when payments have been received.
If you're looking into the future, the graph is forecasting when revenue is scheduled to be received. The revenue is showing on the date when payments are due, or when payments are expected to be received.
Note that the graph does not track income by accrual basis, which is based on when invoices are issued.