I have heard back from Mele20 that disabling Intel RMT worked for her. Mele's a smart cookie and had captured a number of Intel sleep/wake errors in Event Viewer at the times the screen would not wake up. I analyzed one of them and it pointed to the source as the Intel RMT NeverSleep Agent Service. That is what led to my suggestion to disable Intel RMT, since Intel RMT temporarily changes the power plan to Power saver mode and that is exactly what Mele20 was experiencing. During troubleshooting, Mele also created a custom power plan, which may or may not be needed.
So if you have the problem where your power plan is reverting to Power saver mode, try disabling Intel RMT and rebooting. See the second link in my earlier post for how to do this.
Of course, since there are multiple causes for power settings issues, this may or may not work for you. But it's one possible solution that I haven't seen discussed elsewhere.