funny business with speed results

Late October recieved notice that my speed would be increased to 100Mbps. I check my Speed several times a month with Speedtest.net. On Oct 29, my Speed jumped from an avg of 85Mbps to 119Mbps. Exactly 2 months later, 12/31, it dropped back to avg of 85 Mbps and has remained constant for 2 months now. To top it off, for the first time ever, I've had more Service Outages in the last two months than I've had in the last two years! Even more interesting, recieved a call from Xfinity a couple of weeks after the Speed drop, wanting me to spend a couple dollars more a month for 200Mbps. $75.00/month for Internet only. If anyone would have told me that 10 years ago, I would have told them that they were crazy!