Using the grey flashes during motion detection setup is a good technique for masking areas were you have motion that is not of interest. This week, one of my cameras at night continuously detected motion. The problem was created by my neighbor hanging party balloons on a street lamp post. At night when the street light was on, the balloons dim shadows from the street light were in my camera view. Any wind made the balloons move. If I did not have the grey flashes available, I would have never known what created the problem.
I still do not understand how TS relates to motion detection. I now have TS for all cameras set to 4 and use the other settings to tune for motion detection and not light variation detection.