You are correct--the stylus does fit into the grooves. I use mine very slowly and carefully so it does not come out of the groove, and I don't bend long thin points inside the board on some patterns by bashing into them with the stylus. I don't even screw it down--I just let it hold in with gravity. They are pricey, but the quilting comes out PERFECT---like it was computer guided, if you are careful not to start the wrong way at an intersection.