It shows the bandwidth usage from high to low not in order of device name. In the example you gave the device you pointed out just happend to be using the correct bandwitdh amount that put it in the order you wanted. Once the bandwidth amount changes the Nics will move wherever necessary to to fit in the list of usage from high to low.
As far as i know there is not a way to sort them in order of DEVICE which would keep them grouped the way you want them even when some interfaces of that particular Device are not using much bandwidth.
Once you decide Not to group the Interfaces together per Device on the chart options it pretty much becomes "Top 10 interfaces by bandwidth utilization" instead of "Top 10 Devices by Bandwidth Utilization"