So I just called in and the tech gets me to reset my modem...again. After that he logged in and checked the configuration upon my request and he said that everything looked good. I then tried another speedtest and lo and behold my speed is back up closer to what it should! I find that a bit weird but at least it works now.
Since there are packages that have higher download and upload speed, you should get very close to what you pay for. With Speedboost, I get double my download speed on Express for the first 10MB (most of the test sites), however, I'm not sure if you'd get as much of a boost since you're already (perhaps) pushing the limits of the system. Perhaps others who have the higher speed can comment if Speedboost does anything for them.
If you see Shabb's posts in the other thread, he's getting 40-50 on Extreme...
The other option if you were happy with the speed you had before is that you could downgrade and save yourself some money.
Just curious. Are you connected directly to your modem? I remember when I switched from Vz ADSL to cable on TWC a couple years ago, if I went thru the old router I had at the time speeds were significantly slower than if I connected directly to the modem. That led me to buying a more recent wireless router. After replacing my router I could achieve the same speeds thru the router as when directly connected to the modem.