The apotropaic powers of inscriptions 

"Äpotropaic" means "to turn away": the idea was that a demon could be turned away from a house etc by displaying a holy text (or at least a magical text) near the door. The inscription therefore had to be clearly visible - at head-level, and outside the door (no point in letting your demon come inside before he could read the magic). The Tel Yayit stone doesn't fulfill these criteria: it was being used in an internal wall, inside a dark room, was about 3 feet off the ground, and was very faint. The archaeologists who found it missed it themselves until the last day of excavation, when they just happened to see it early one morning in ideal conditions, in the low raking light of the rising sun. Tho the setting sun would have done just as well. But the point is, in a dark room 3 feet off the ground, no demon is going to see it or read it, and even if he were a midget-demon, he's already inside, so what's the point? So, no apotropaic powers for this stone.