Not Getting Full Support for DOCSIS 3.1 32x8

Hello,

On the Xfinity gateway I was seeing at least 5 locked upstream channels. I just purchased a new Motorola B12 cable modem DOCSIS 3.1 32 x 8 and I am only seeing 4 upstream locked channels and my internet is half the speed that it was or more. I am on 1000Mbps plan and I am only seeing at best 300Mbps down and 5Mbps up. When I hook up the Xfinity Xfi gateway the speed is normal and getting around 900Mbps down and 150Mbps up. Does anyone know what could be going on? This is also my 3rd cable modem so far in the last month trying to get speeds at least close to what they were with the Xfinity gateway. Do I need to take my Motorola B12 to Xfinity to have them adjust some settings or can they do this over the coaxial cable?

Thanks for any help on this as this is getting very frustrating with losing all this speed when using my own cable modem, 3 different ones, and then plugging in Xfinity gateway to see normal speeds, or reasonably normal. 

I have gone through all the troubleshooting steps and nothing has helped. The main thing I see is the wiring or something may have changed, but without changing any other solitary thing; swapping the Xfi directly out for the B12 the performance is significantly reduced and I’m only seeing 4 upstream channels.