Z-Wave settings Last Sent vs Last Received

In the settings page, there are two columns with the above titles. What are they for?

Last sent is when HE sending data to the device. Last received is when the device checking in or reporting to the hub.
I find this Two columns very useful for checking the status of my Z-Wave devices since it's similar to device health in ST. I monitor it after a hub reboot and expect hardwired devices to check in within a day or less and battery devices within 2 days with the exception of my smoke detectors.

Thank you. That's what I thought.