The discrepancy between the paid out amount and the revenue you have for a given month comes from the fact that it takes some time for the money to be eligible for payout from the time the user makes the payment. It's withdrawn from the users account, and then Visa/Mastercard holds on to it, before it's transferred to you account in Adyen and ready for payout. Because of this delay, some of the money from the last days of the month will not be on the payout the occurs the 1st, but will be included in the next payout. So the money is carried over, it's just that this happens again for every month.
So there's always going to be a bit of a diff between the revenue for a given month and the payout you receive the 1st.
To reconcile this and see the status you can use the accounting report in Admin > Accounting > Account reports