Upload Issue again

It made it almost a full three months that I was able to stream videos at any resolution without buffering with only the intermittant issue that would last no more than 48 hours or so. But I knew it couldn't last. While download speeds average 16.7Mbps upload speeds drop to an average of 3.3Mbps which means uploads are virtually shutoff at times. Those averages were attained between 1:00 am and 7:00 am 11:00 am to 3:00pm any day of the week. This has lasted more than two weeks now just to make sure it was a real issue and not a whiny complaint generated by a transient glitch. Currently all videos launch in 144p or switch back to that within seconds of choosing 360 or 480 regardless of the time of day with the corresponding state code of 12.1.9 lasting from 30 seconds to 10 minutes occuring roughly every 15 to 30 minutes.

The modem is plugged directly into the wall, it's been rebooted with the router bypassed, and though there is zero chance it could be related another desktop computer was used (only because I'm always asked to try that).

I have not called the repair number since they have not yet been able to offer any fix and this is where they suggest I bring the issue in the hope that it might catch the eye of a moderator who can delve into the irritation with a better chance of success. The last one to deal with this posted it would be looked into and without another communique the issue was corrected, more than less, for the period I stated, nearly 90 days (76 to be exact). 

I'm on Gen4 having no reason to upgrade to Gen5 (even though technicians have advice me to do so) since I already have a router, 50 gigs of time, and no issue with download speeds beside the fact that it would cost me something like $40 more a month.

I'm open to suggestions.

It occured to me that I didn't present max speeds which I'm concerned might be a bit of wishful thinking. 69.1Mbps download and 86.8Mbps upload. (And who said this wasn't a gamers provider)