Here is the total bandwidth for IP address 192.168.1.1 (there are two entries in the list for 192.168.1.1, but they both show the same graph):

And here is the router's total bandwidth:

All this was when there was absolutely no other devices even connected to the router, except for my linux laptop to view the graph, and i made sure it had no net traffic of its own.
So the traffic starts out being designated as hostname 'gargoyle', then for some reason it just disappears, won't show up under ANY hostname, and only shows up under 'total bandwidth'. Whatever is causing this issue is likely also the cause of the QoS issue; after all, QoS can't limit traffic to 192.168.1.1 if the traffic supposedly isn't going to 192.168.1.1