I have asked in-house if anyone has the contact to the right person at Microsoft, so if we find the contact information we can send it to you. We have also checked how the EyeX Engine handles sleep mode/away mode. The default setting is to turn off the eye tracker to save battery, but there might be some changes that can be done there. Both those options will obviously take some time.
Meanwhile, it would be good to know exactly what code you use to turn off the screen. Does the tablet go into sleep mode, away more or something else? Moreover, would it be a short-term option for you to “fake” turning off/on the screen just by showing/hiding a black always-on-top window? We have used that method when prototyping this concept, to avoid the problems with sleep mode/away mode and get a swift response from the computer when entering in front of it.