The Belkin is not a culprit because it's doing what it's supposed to do.
Internet speed will be limited to the lowest-rated component of your connected devices...aka, chokepoints.
I researched the specs of your equipment. The LAN port on your Belkin is Fast Ethernet with a max throughput of 100 Mbps. The WAN port on your DPQ3212, however, is Gigabit Ethernet with a max throughput of 1000 Mbps.
If your speed test measured 94.6 Mbps through the Belkin, it's a good test because the Belkin is limited to 100 Mbps. You can't get 150 through a 100 Mbps port.
179 Mbps is good on a 150 plan. Cox is using "excess capacity" to provide temporary speed bursts at the beginning of your downloads.