If the last hop is showing a problem, then the problem is on the return trip back to your computer. Due to the limitations of the 'traceroute (includes tracert, Ping Plot, and any other ICMP like utilities)', you can only see the data path your packets take TO the destination.
If the network path is asynchronous (takes a different path back), then you are only seeing half the data. I have to run the other half for you.
It will have to wait until I am in the office, but generally speaking, the problem is going to lie in the Level3 network. Your ISP has been switching over to Level3, as has every other cable ISP in the U.S. Level3's network is badly oversold, but they are cheap, so they are attractive to the cable ISP's who are struggling to make money.
I'll run the trace when I get into the office.