The bandwidth usage is consist of ingress (uploads to your node) and egress (downloads from your node).
In the Payout information you have only downloads, confirmed by your node, the customer and the satellite. So if you see a discrepancy between downloads on the bandwidth graph and in the Payout information, then your node may have problems with submitting orders, see Failed to settle orders {"error": "order: unable to connect to the satellite.
You may also check the orders folder near the config.yaml file (in case of Windows GUI it’s in the "C:\Program Files\Storj\Storage Node\" folder), do you have orders older than 48h? If so, you need to figure out in your logs why your node cannot settle them.