Why is My Devices list different from All Devices in Find My iPhone on iCloud?

This is perplexing. When I go to iCloud and look at the list in My Devices I see an accurate list of all of my devices (man I have too many Apple devices). But when I go to Find My iPhone on iCloud I see all of the devices in the My Devices list PLUS additional devices?

I believe that My Devices are all the devices that I am signed into. But if this is so, what are the additional devices on Find My iPhone? And how can I remove these devices?