I don’t think there are any problems with your English.
The “Precision Gaze Mouse” program is not mine. I mentioned it just because it claims to do “precise mouse cursor control” in a similar way with what you described. If you are not satisfied, or it is error prone, then ignore it and stick with your own way.
I believe tobii knows everything about the potential of their devices. The reason they don’t add those features is not on the tech side.