Fios internet slow at night.....tech support not helpful

Hello there! Every night for the past 2 months from 5pm-12am my internet has been slow. I'm currently on the 75/75mb plan and I'm getting about 5-10mb down and 25-30mb up between 5pm-12am every night. This is on wireless and ethernet connections. Of course I did the basic trouble shooting, reboot router, restored router, turned wifi off..blah blah blah.... but still get horrible speeds during the night. Speed test are from various sites and on various servers....all with pretty much the same results. Today, I finally called Fios tech support and they had me do the same thing and also they reset some things on their end. They also had me do speed tests from ONLY their site...http://my.verizon.com/services/speedtest/. Which at first was getting horrible results as well. After an hour on the call with support the tier 1 guy went to go ask his network tech guy for some help. The network guy had me install "Verizon Fios Speed Optimizer" (http://my.verizon.com/services/speedoptimizer/fios/) on my desktop computer which is connected via ethernet and then had me run a speed test from their site specifically. And of course I was getting the correct speeds 75/75mb. But then I ran speed test from various sites and I'm still getting horrible speeds. When I told the tech about speed results from other sites he said they can't go by those results because they don't control the those servers. He also knew exactly what my speeds were (before I told him) when I ran the test from their sites. Now, the only computer in my house is getting the proper speed but all of my wireless devices are really slow. Verizon techs said they wouldn't do anything else because my speeds are correct from the results from the one computer and their own speed test site. It's my understanding that this "Speed Optimizer" resets TCP stacks but it makes no sense that everything is fine after midnight and during the day before 5pm. Does anyone have any suggestions? Aaaanndddd to put a cherry on top from verizon speed test site: "You have exceeded the limit of 30 tests per day"