Hi, i guess not everybody is sharing his/her experience at the community... But i have a UMI PLUS also, and my phone has the same issue. Let's say, 1 of the 25 touches misses... really annoying
What i have tried:
Running Android 6.o (out of the box)
reset phone
found some apps ( touchscreen calibration, Quick Tuneup-Phone Calibration) all these kind of apps will make it worse....
So i decided to upgrade to android 7. During setup i switched off the fingerprint scanner, because it does not work very well. My feeling says the touch screen seems to be more smoothly. I minor update was announced after this upgrade, so i installed it (could not read the details or releasenotes because it was written in chinese .. Still i notice some missed touches, but not as much as with Android 6.
So i do not want to try this SGS app, because of my experiance with such apps in Android 6. I prefer a good fix from UMI it self