Customer owned cable modem (Motorola MB7420) and router (TPLink Archer A7), low internet speeds

I bought at the beginning of Febuary a Motorola cable modem MB7420 and a TPLink Archer A7 wifi-router.  I have Performance Pro as my tier for internet service in the Denver CO area.  Recently, in the last day or so, my internet downlink speeds have fallen to ~6 Mbps.  I've called Customer Support several times tonight to see if this can be fixed.  According to the representative, there is something wrong with my cable modem.  I will post the modem activity logs.  I have cycled the power several times manually and had the troubleshooting software on Xfinity's site reboot the modem.  This SHOULD have updated the firmware, but I'm not so sure.  Also, the rep. I spoke to tonight said "Xfinity does NOT do firmware updates for customer owned modems, only the manufacturer can do that." I just so happened to find Motorola's official policy on firmware updates for their purchased products  Motorola cable modem firmware update policy 

When you view the link's page, you can readily see Motorola does NOT update their products firmware, only the ISP (Xfinity in this case) can update it by "pushing it".  The process is Xfinity must receive the new firmware FROM the vendor, approve the firmware update, make additional changes, and then "push it" to the consumers modem.

Xfinity, you might just want to have some retraining for your tier 1 customer service reps, because, obviously, this last rep I spoke didn't know about the "push" process.  OR- this could have been a deliberate obfuscation they are trained for, with the hope the customer will give up, return the 3rd party device and just buy/rent a modem from Xfinity. 

Here are my modem's admin page and logs

Not that I'm implying that Xfinity DOES have deceptive practices, I AM saying that as a business that is under US Federal regulation, you MIGHT want to have as much distance from APPEARING to have deceptive/manipulative business practices as possible.

I do hope someone with enough competance can help me fix this situation.  I'd rather not leave Xfinity.  Been a customer since 2013 and have only had this problem once before.