Daily Internet Speed drop

[SrFox]

Can somebody explain please why does my speed drop everyday at about 5:00 pm?
I am an Internet tech and experienced IT tech.
I am direct wired to my router (not WiFi)

Speed drops from over 200 Mbs to around 3 Mbs every day at about 5:00 pm and comes back at high speed again at about 8:00 the next morning.  I have been monitoring this for about 2 weeks now.  I can not seem to get answers from anybody.  Xfinity has promised that a high level tech will call me back within and hour but I have never heard back from anybody.

Today, on Sunday night at 6:00 pm am getting 11 Mbps.  Wow.   It was at 231 Mbps until 5:00 pm.

I pay for 200, why am I not getting it?

By the way, I change nothing on my end to that causes any speed change.   I have done many router reboots as well so please don't suggest that.  
I also have tested my friend's system near me and they have the same issue.

[BruceW]

If you want to troubleshoot this yourself, please see Internet Troubleshooting Tips. If you still need help, please post your modem or gateway's model number and signal information, especially downstream power levels and SNR, upstream power levels, and error log.

If you can't find the problem or you'd rather have Comcast take care of it, call them at the phone number on your bill or 1-800-Comcast, or use one of the options on https://www.xfinity.com/support/contact-us/. Insist they send a tech out to identify the cause and correct it.

If the tech finds bad coax, splitters, amplifiers, or connections in your home (even if Comcast originally supplied them) you'll probably have to pay for the visit unless you have their Service Protection Plan (https://www.xfinity.com/support/articles/service-protection-plan, closed to customers that don't already have it). If the trouble is due to a faulty Comcast rental device, or anything outside your home, you shouldn't be charged.

[SrFox]

If you want to troubleshoot this yourself, please see Internet Troubleshooting Tips. If you still need help, please post your modem or gateway's model number and signal information, especially downstream power levels and SNR, upstream power levels, and error log.

Thanks for the reply.

No point in posting those numbers as they do not change.  Only the speed does. 

As I posted, I am an internet tech with many years of experience.

Xfinity has promised to send somebody out, if that ever happens.  They even offered it for no charge.  There is no equipment inline to fail, and again, I change nothing.  It happens on Comcast's end and I am sure I am nowhere near any data cap they may have.  I am in the first week of my data cycle.

[SrFox]

I am still waiting for an Xfinity tech to come out for a service call.  They told me it would be 48 to 72 hours.  They are now officially 24 hours overdue on the 72 hour max estimate.

By the way, my speed tonight (started at about 4pm) is at 3.5 Mbps