I live in Pensacola, and had the Ultimate package too. I purchased the SB8200 modem also and upgraded to Gigablast. I had the exact same experiences with connection speeds that you did. I reset the modem and router several times too. But, when I disconnected the router and went straight from the modem to the computer with an ethernet cable (CAT-6) and reset everything, my speed jumped up to 950Mb. When I reconnected through the router, my speeds plummeted.
In my case it was the router. I had a Linksys WRT1900ACS which should have worked fine, but didn't. I made sure the router had the latest revisions. I upgraded my router to a Linksys WRT3200ACM and everything has worked fine since.
I'm now consistently reading about 950Mb/down 36Mb/up and 11ms ping to the Cox New Orleans site on Speedtest.