Ultimate only gives me 10 mbs rather than 20

I am paying for ultimate which is suppose to be 150/20 but I rarely see the 150 (usually around 120).  I NEVER see more than 10 even on their own speed test (which is skewed compared to the freebie speed tests on other sites).

I have the proper modem and router for the ultimate package and the computer I am using connects through a 4-port hub to the cable modem.  I am paying for three IP addresses because I am a gamer and want the dedicated IP address to the game system so I do not have to port-forward with it.

None of the systems (either the ones that are connected to routers and then the hub then cable modem or the one that is directly connected to the hub then the cable modem) get more than 10 rather than the 20 I am suppose to get.

The hub I am using is suppose to provide straight passthrough speeds but could it be the problem?

Lance