Here is your problem "Power Level 55 dBmV" that is way too high, recommended is "~40-49dBmV". Your bottleneck seems to be the upstream having too much power thus causing you to fallback to 16QAM giving you the lower upload speeds. It could be as simple as moving the modem to the first cable splitter in your house, or it could be something on Time Warner Cables network. If the latter you'd have to call them, but how is your modem connected? But if your not sure what to do, then you can just call and ask for tier 3, they can run tests and go from there.