inconsistent speeds, problems with possible throttling

I ran a few speed tests tonight and have found extreme variations in my download speeds. The only place I was able to get the "correct" speed was on the Cox speed test which runs only on the Cox network. Going outside of that network means lower speeds. The other issue I have has been with Hulu. EVERY time I try to watch something on Hulu I end up getting an error stating the network connection was lost. I don't get this type of error with Netflix or Youtube so I have suspicions that Cox is throttling me on Hulu.

These tests show that I am not getting the 50Mbps that I am paying for. I have worked for an ISP in the past so I actually do have half a clue here. I ran these tests on my home PC which is connected directly to my modem via an ethernet cable. I realize that the servers these tests were run on could have other traffic at the same time I was conducting my speed tests however it's pretty clear that whenever I connect to a website outside of the Cox network, I do not get the 50Mbps connection.

I have no firewall running, my computer is connected directly to my modem (so no wireless is involved here), I am running Windows 7, I have no viruses or malware.....Here are my current modem signals....